Harley Hahn's
Internet Advisor

Chapter 14...

Mailing Lists

For many years — even before Usenet, and long before there was a Web — people have been using mailing lists to hold discussions. In fact, mailing lists are almost as old as the Internet itself.

Today, there are a vast number of mailing lists, even more than the number of Usenet groups. Many of these lists are open to anyone, and it is easy to participate: if you know how to use mail, you already know most of what you need to know. In this chapter, I will explain how mailing lists work, how to join them, and how to find the ones that interest you.

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The Basic Ideas

A MAILING LIST is a facility that allows people to participate in an ongoing discussion via email. There are tens of thousands of mailing lists on the Internet. Many of them are private (and probably of no interest to you or me), but a large number of the mailing lists are — like Usenet discussion groups — open to anyone. When you join a mailing list (which is free), we say you SUBSCRIBE to the list. When you quit the list, we say you UNSUBSCRIBE.

Within a mailing list, messages are circulated by mail. The idea is simple: each time someone sends a message, a copy of that message is sent to everyone who has subscribed to that list. Thus, to participate in a discussion about a particular topic, all you have to do is subscribe to a mailing list devoted to that topic. From then on, a copy of every message that anyone sends to the list will be sent to your mailbox automatically. When you unsubscribe from the list, you will stop receiving messages.

Each mailing list is controlled by a person referred to as the LIST OWNER. In most cases, the owner is the person who started the list or, perhaps, inherited the job from someone else. The duties of the owner of the mailing list are minimal, because, as I will explain in a moment, most of the work is done by an automated program.

The basic job of the list owner is to monitor the messages and sort out any problems that may arise. The owner also creates a document, called a WELCOME MESSAGE, that is sent to each person who subscribes to the list. The welcome message contains general information about the list, including its purpose, any rules regarding the discussion, and a description of any special features. The welcome message also contains instructions on how to unsubscribe from the list.

Some mailing lists are MODERATED, which means that a person, called the MODERATOR, decides which messages are sent out. In most cases, the moderator is the list owner, although it can be a different person.

Most lists are not moderated, and when you send a message, everyone sees it. With a moderated list, the message is first sent to the moderator. The moderator reads all the incoming messages and decides which ones should be sent to the list.

The main advantage of a moderated list is that the discussion stays more focused than with an unmoderated list. However, with a busy list, moderating can require a lot of time, and it is necessary to find someone willing to volunteer the hours.

We use the terms TRAFFIC or VOLUME to refer to the average number of messages sent to a particular list. Some mailing lists have low traffic, and you may not see more than a few messages a week, or even in a month. Other mailing lists, however, have a lot of traffic, and a busy list can fill up your mailbox quickly. It is not uncommon, for example, to go away for a week's vacation and come back to find your mailbox overflowing with messages from your favorite mailing list. For this reason, some mailing lists provide a way to stop the messages temporarily when you know you are going to be away for a while. (I will show you how later in the chapter.)

When a list has a lot of traffic, it can be inconvenient to receive a lot of separate messages. Some mailing lists offer an alternative. Instead of receiving separate messages, you can choose to have all the messages for each day collected and sent to you as one large message, called a DIGEST.

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How Are Mailing Lists Different
from Usenet Newsgroups?

In some respects, mailing lists are similar to Usenet newsgroups (which I discuss in Chapter 13). They both cover a large variety of topics discussed by people all over the world. There are, however, important differences.

The articles in a Usenet newsgroup are stored on news servers around the Internet. When you post an article to a newsgroup, the article starts from your news server, and makes its way around the world by being copied from one server to another. Mailing lists are different. Each mailing list is managed by a MAILING LIST PROGRAM (sometimes called a LIST SERVER) running on a specific computer. When you send a message to a list, the mailing list program receives the message and sends a copy to everyone who is subscribed to the list.

To read the articles in a Usenet newsgroup, you have to use a special program, called a newsreader, to connect to a news server. To participate in a mailing list, all you need is a regular mail program.

This means that, when you subscribe to a mailing list, all the messages from that list are sent to your mailbox automatically. You do not pick and choose what you want to read. (Although you can always delete messages without reading them.) With Usenet, you need only look at a newsgroup when you feel like it, and it is easy to browse from one group to another.

Thus, Usenet lends itself to exploring and skimming. Once you learn how to use your newsreader, it is simple to take a peek at any newsgroup you want, whenever you want. With a mailing list, you must subscribe and then wait for new messages to arrive in your mailbox.

For this reason, people are more selective about which mailing lists they subscribe to, compared to which newsgroups they read. This leads to a mailing list culture in which you see more serious, and longer, discussions than on Usenet. For example, many mailing lists are used by researchers and students for scholarly collaboration, something that is more difficult to maintain on Usenet. In fact, it is common to find mailing lists in which the participants have been talking together for months or even years. As such, these lists develop a community spirit. Although some Usenet newsgroups do develop this type of spirit, most groups are more like open forums, with people tending to drift in and out.

Like Usenet, mailing lists offer a lot of variety. There are lists for just about any topic you can imagine, and, in fact, there are a lot more mailing lists than Usenet newsgroups. However, mailing lists tend to have more wheat and less chaff. In particular, there is virtually no spam — the unsolicited advertising that plagues Usenet.

The final difference I want to mention relates to names. Usenet newsgroups have names that consist of more than one part, such as:


The first part of each name shows the hierarchy (in this case, alt, biz and rec).

Since every mailing list is run from a particular computer, there is no need for a standardized naming system. All that is needed is a name that uniquely identifies the list on its own computer. Thus, mailing lists use simple, one-word names. I will show you how the system works in the next section. For now, here are a few examples:

Mailing List Description
abstract-art-lAbstract art
eat-lFood and drink
humorHumor and jokes

What's in a Name?


One of the oldest networks to support a large number of mailing lists was called Bitnet. (I will talk about Bitnet later in the chapter.) Within Bitnet, it was necessary to differentiate between a user name and a mailing list name. For this reason, people used the convention that all mailing list names would end with the characters -l (a hyphen followed by a lowercase "L"). For example, the Bitnet mailing list devoted to travel was called travel-l.

When you talk about such names, there are several ways to pronounce the -l characters. Many people pronounce the "el" but not the - character, so you might hear someone say, "I subscribed to the 'travel el' list."

Technical Unix people are more likely to pronounce the - character as "minus", because that is the custom with Unix. So a Unix person would talk about subscribing to the "travel minus el" list.

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Mailing List Programs:
Listserv, Listproc and Majordomo

As I mentioned earlier, every mailing list is managed automatically by a mailing list program. This program handles the details associated with running a list: processing subscription requests, making sure that messages are distributed to everyone on the list, creating digests, and so on. There are three common mailing list programs you will encounter on the Internet: LISTSERV, LISTPROC and MAJORDOMO.

A mailing list program has two jobs. First, there is the basic job of distributing the messages. The mailing list program receives every message sent to the list and sends a copy of the message to each person who has subscribed to the list. (If the list is moderated, every message is first sent to the moderator. The moderator then tells the program which messages to distribute.)

The second job performed by a mailing list program is to carry out various administrative commands. Anyone can issue such commands to a mailing list program by sending it a message with a particular format (which I will explain later in the chapter). When your message arrives, the program reads it and carries out your commands.

For example, to join a mailing list, you send a message to the mailing list program that administers that list. Within the message, you put a subscribe command. To quit a list, you send a message containing an unsubscribe command. Although there are a number of different commands you can send to any mailing list program, you really only need to know a few of them.

Thus, a mailing list program receives two types of mail: administrative messages that contain commands to be carried out, and regular messages that are to be distributed to everyone on the list. To keep things straight, each mailing list has two different addresses. The SUBSCRIPTION ADDRESS is the one to which you send commands. The LIST ADDRESS is the one to which you send messages. Here is an example.

In the last section, I mentioned a mailing list called cinema-l. The list address is:


This is the address to which you would send regular messages. Anything sent to this address will be distributed to everyone on the list.

The subscription address is:


This is the address to which you would send administrative commands, for example, to subscribe or unsubscribe to the list.

In most cases, a single mailing list program handles all the mailing lists on a particular computer. For example, the Listserv program on american.edu manages all the mailing lists on american.edu. Thus, the subscription address will be the same for every mailing list on the same computer.

Figure 14-1 contains a few more examples, showing the subscription addresses and list addresses of the mailing lists I mentioned in the previous section.

Figure 14-1: Examples of mailing lists

Mailing List Subscription Address List Address

What's in a Name?


Listserv, Listproc and Majordomo are all mailing list programs.

Listserv is the oldest. It was originally developed by Eric Thomas in 1986 for IBM mainframe computers on the Bitnet network (which I discuss later in the chapter). Later, Listserv was converted to run on other Bitnet computers, particularly DEC's VMS systems. The name Listserv stands for "list server".

As the Internet became popular, Listproc was created to be the equivalent of Listserv for Unix computers on the Internet. Listproc was developed by an organization called CREN (Corporation for Research and Educational Networking), the successor to Bitnet. The name Listproc stands for "list processor".

Majordomo was developed in 1992 by Brent Chapman, also to run under Unix. Majordomo is written in Perl (don't worry if that doesn't mean anything to you). Although it can do the basic job, Majordomo does not have as many features as Listserv and Listproc. The name Majordomo is taken from the term "majordomo", used to describe the chief steward in a large household, such as a palace. Within such a household, the majordomo is the servant with the most responsibility, the one who performs the most important jobs, while coordinating the activities of the other servants.

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Subscribing and Unsubscribing
to a Mailing List

Subscribing to a mailing list is easy. All you need to do is mail a short message to the subscription address. The subject of the message can be anything you want (it is ignored). In the body of the message, put a single line containing a subscribe command. The format is as follows.

For a Listproc or Listserv mailing list...
      subscribe   mailing-list   your-first-name   your-last-name

For a Majordomo mailing list...
      subscribe   mailing-list

(The only difference is that, for Majordomo, you do not need to specify your first and last names.)

Here is an example that illustrates how to subscribe to a Listserv or Listproc mailing list. Let's say your name is Warren Peese, and you want to subscribe to the humor mailing list I mentioned in Figure 14-1. To do so, send the following message:

To: listserv@american.edu
Subject: anything you want

subscribe cinema-l Warren Peese

When you send commands to a mailing list program, it doesn't matter what you put in the Subject line. However, I always put something descriptive to make it easier to recognize the message when I see it in my outbox. For example:

To: listserv@american.edu
Subject: subscribe cinema-l

subscribe cinema-l Warren Peese

The next example shows a subscription command sent to a Majordomo list. The main difference is you do not put your first and last names:

To: majordomo@itg.uiuc.edu.com
Subject: subscribe abstract-art-l

subscribe abstract-art-l

Notice that, in both cases, you do not have to specify your mail address. The mailing list program will pick up your address automatically from the header of your message.

To unsubscribe from a mailing list, send a message to the subscription address. In the body of the message, put a single line containing an unsubscribe command. The format is as follows:

      unsubscribe   mailing-list

Here is an example:

To: listserv@american.edu
Subject: unsubscribe cinema-l

unsubscribe cinema-l

As a summary, Figure 14-2 shows the general format for subscribing and unsubscribing to a mailing list.

Figure 14-2: Subscribing and unsubscribing to a mailing list

Subscribing to a Listserv or Listproc mailing list...

   To: subscription-address
   Subject: anything

   subscribe  mailing-list  your-first-name  your-last-name

Subscribing to a Majordomo mailing list...

   To: subscription-address
   Subject: anything

   subscribe  mailing-list

Unsubscribing to a Listserv, Listproc or Majordomo mailing list...

   To: subscription-address
   Subject: anything

   unsubscribe  mailing-list

Note: With Listserv, you will sometimes see signoff command used as a synonym for unsubscribe. The word signoff comes from the days of the old IBM mainframe computers, which were the original home of the Listserv mailing lists.

When you subscribe to a mailing list, the mailing list program will send you a copy of the welcome message for that list. Save this message, as it will have information that may come in handy later. In particular, the welcome message will contain instructions for unsubscribing to the list.

If you subscribe to more than one list, an easy way to store the welcome messages is to create a folder (directory) with the name of Mailing-lists. Each time you get a welcome message, save it in this folder. In this way, you can find any welcome message just by looking in your Mailing-lists folder.

Once you start reading mailing lists, you may end up with a lot of messages in your inbox. If so, here are two hints that can help.

First, you can get an extra email address just to use for mailing lists. That way, the mailing list messages won't get mixed in with your regular mail. Alternatively, if your mail program has a filtering feature, you can use it to process your mailing list messages automatically as they arrive and put them in a special folder.

— hint —

If you are new to mailing lists, you may be tempted to subscribe to several at the same time. My advice is to start with only one list. Wait a week and see how much traffic the list generates before you subscribe to another list.

If you subscribe to several high-traffic mailing lists at the same time, you will receive a lot of mail within a short time, and you may find it difficult to sort out the various messages.

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Keeping the Addresses Straight

As you know, a mail address has the following format:


where hostname is the name of a computer. Mailing lists use two different addresses:

  • Subscription address, to which you send commands
  • List address, to which you send messages for the list

The name in a subscription address will be the same as the name of the mailing list program: either listserv, listproc or majordomo. The name in a list address will be the name of the mailing list itself.

Here is an example. Consider a Majordomo mailing list named abstract-art-l on the computer itg.uiuc.edu.com. The two addresses are as follows:

  • Subscription address: majordomo@itg.uiuc.edu.com
  • List address: abstract-art-l@itg.uiuc.edu.com

It is important to keep these addresses straight. You should use the list address only to send regular messages. For everything else, use the subscription address.

— hint —

When it is time to unsubscribe, by sure to send the request to the subscription address.

It is common for beginners to send an unsubscribe request to the list address, rather than to the subscription address. Not only will this not work, but a copy of the message will go to all the people on the list, annoying everyone.

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Mailing List Commands

One of the jobs of a mailing list program is to carry out commands. To send such commands, you mail a message to the subscription address for a list. Within the body of the message, you can put as many commands as you want, one per line. The subject of the message can be anything you want (it is ignored).

When your message is received, the mailing list program will process it, one line at a time. So far, I have described only two commands (subscribe and unsubscribe). However, there are others, the exact details of which vary depending on what type of mailing list program is being used.

In Figures 14-3, 14-4 and 14-5, I have summarized the basic commands for the three main mailing list programs: Listserv, Listproc and Majordomo.

Figure 14-3: Summary of important Listserv commands

Subscribing and Unsubscribing...

   subscribe  mailing-list  your-first-name  your-last-name
   unsubscribe  mailing-list
   signoff  mailing-list   [same as unsubscribe]

Information About Lists...

   lists global/keyword   [send names of lists containing keyword]
   info  mailing-list   [send information about mailing-list]

Help Information...

   help   [send general help information]
   info ?   [send a list of help topics]
   info  topic   [send information about topic]

Turn Mail Off and On...

   set  mailing-list  nomail   [turn mail off temporarily]
   set  mailing-list  mail   [turn mail back on]

Send Messages in Digest Format...

   set  mailing-list  digest   [send messages in digest format]
   set  mailing-list  nodigest   [send messages in regular format]

Figure 14-4: Summary of important Listproc commands

Subscribing and Unsubscribing...

   subscribe  mailing-list  your-first-name  your-last-name
   unsubscribe  mailing-list
   signoff  mailing-list   [same as unsubscribe]

Information About Lists...

   info  mailing-list   [send information about mailing-list]

Help Information...

   help   [send general help information]
   info  topic   [send information about topic]

Turn Mail Off and On...

   set  mailing-list  mail postpone   [turn mail off temporarily]
   set  mailing-list  mail ack   [turn mail back on]

Send Messages in Digest Format...

   set  mailing-list  mail digest   [send messages in digest format]
   set  mailing-list  mail ack   [send messages in regular format]

Figure 14-5: Summary of important Majordomo commands

Subscribing and Unsubscribing...

   subscribe  mailing-list
   unsubscribe  mailing-list
   signoff  mailing-list   [same as unsubscribe]

Information About Lists...

   info  mailing-list   [send information about mailing-list]
   lists   [send summary of all listson that computer]

Help Information...

   help   [send summary of commands]

Most of the time, you will only have to use the subscribe and unsubscribe commands, but the others are there if you need them. My suggestion is to send for general help information to get a full list of commands. You can then ask for more specific instructions if you need them.

For example, to request general information from a Listserv program, you would use the help command. Here is a message that does just that:

To: listserv@uga.cc.uga.edu
Subject: help information request


When the Listserv program receives this request, it will send you the help information by return mail.

If you want to send more than one command, remember to put each one on a separate line. (The info ? command requests a list of all the help topics. See Figure 14-3 above.)

To: listserv@uga.cc.uga.edu
Subject: help information request

info ?

When you mail these types of messages, there is a potential problem I want you to be aware of. The mailing list program reads your message and processes it one line at a time. If the message happens to have any lines after the last command, the program will try to interpret them as commands, which will result in error messages.

This will happen if you have set your mail program to append a signature to the end of each message (see Chapter 5). It will also happen if you are using a free email facility that puts an advertisment at the end of each message.

To avoid such problems, put a single line with the word end after the last command. This tells the mailing list program to stop processing commands. Here is an example:

To: listserv@uga.cc.uga.edu
Subject: help information request

info ?
These two lines will be ignored by the
mailing list program.

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Finding Mailing Lists

There is no central directory of mailing lists, so when you are searching for a list devoted to a particular topic, there is no single place to look. I do, however, have four suggestions.

First, my Yellow Pages book (Harley Hahn's Internet Yellow Pages) is an excellent place to start. In the book, I have thousands of different items, and many of them have mailing list information (along with Web sites and Usenet groups). Just look up the topic you want, and there is a good chance you will find an appropriate mailing list.

The second place to look for mailing lists is on the Web, where there are a number of well- maintained Web sites devoted to collecting and categorizing mailing list information. These sites contain information on a huge number of lists, so, with a little work, you will probably be able to find what you want. These Web sites are independent of one another, so my suggestion is to search them all before you make a final selection.

Third, check Web sites devoted to the topic in which you are interested. Many such Web sites support their own mailing lists, or have links to lists. For example, if you are looking for a mailing list for model railway discussion, spend some time visiting model railway Web sites, and you'll probably find a mailing list or two.

Finally, there are a number of services that allow you to start your own Web-based mailing list for free. We will discuss such services in the next section. These services make it easy to search through their public mailing lists, which makes them good resources for finding what you want. (The Web addressees are at the end of the next section.)

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Starting Your Own Mailing List

There are two ways to start your own mailing list. First, you can find a place that runs a mailing list program (Listserv, Listproc or Majordomo) and see if someone will agree to create a list for you.

The best place to start is with your ISP. Many ISPs will set up mailing lists for their customers, either for free or for a fee. If you work or study at a university, you can probably get one of the system administrators to start a mailing list for you. Ask around to see what the local policy is.

As an alternative, there are a number of companies on the Web that provide "free" Web-based mailing lists. These services allow you to send and receive messages via your Web browser, as well as by regular mail. The interface for these lists is also designed to be used over the Web, and it is usually easy to subscribe and unsubscribe.

Of course, such services are not really free. Everyone who subscribes to your mailing list will have to look at advertisements, either at the Web site or inserted into the actual messages. Moreover, reading messages via a Web browser is a lot slower (and a lot more frustrating) than using your own mail program.

For this reason, these services are not my first choice. However, they do provide a practical alternative if you do not want to pay a fee, and you can't get your ISP or anyone else to set up your list for free. This is especially true if you want a small mailing list for a very specific purpose. For example, many people set up a free Web-based mailing list to keep in touch with the members of their family. What could be more cool than having your own family mailing list?

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Mailing List Gateways

Although there are important differences between mailing lists and Usenet newsgroups, they both contain a similar type of information: messages (or articles) sent in by various people. Because of this similarity, it is possible to arrange for a mailing list to have a corresponding Usenet newsgroup. This means that every message sent to the mailing list is automatically posted to the newsgroup, and every article posted to the newsgroup is automatically sent to the mailing list. In such cases, you can participate by subscribing to the list or by reading the newsgroup. Either way, the content will be the same.

This type of facility requires a special program called a GATEWAY. The job of a gateway is to provide an automatic connection between two different types of information systems. In this case, we are talking about a Usenet/mailing list gateway. (We sometimes use the word "gateway" as a verb. For example, I might say that a mailing list is gatewayed to a particular Usenet group.)

The reason I mention all of this is because there is a well-known set of mailing lists that are gatewayed to an entire Usenet hierarchy. These mailing lists used to belong to a network called BITNET, and, some years ago, it was felt that some of them should be available via Usenet as well. To make this happen, a Usenet/mailing list gateway was created along with a set of newsgroups, one for each mailing list. All of these newsgroups are in the bit hierarchy.

Bitnet was started as an academic network in 1981 and grew so much that, by 1992, it connected about 1,400 organizations (mostly universities and research institutions) in 49 countries and supported several thousand mailing lists. Since then, however, the Internet has become the global network of choice. By the end of 1996, the Internet had absorbed most of what used to be Bitnet. Still, a large number of the mailing lists exist to this day, and some of them are gatewayed to Usenet newsgroups within the bit hierarchy.

The Listserv mailing list program was originally developed to run on Bitnet, and it is this program that supported the Bitnet mailing lists for so many years. For this reason, many of the bit Usenet groups have the word listserv in their name. You can see this in Figure 14-6, which shows a few examples of Bitnet mailing lists along with their corresponding Usenet newsgroups.

Figure 14-6: Examples of gatewayed Bitnet mailing lists

Mailing List Newsgroup Description
blues-lbit.listserv.blues-lBlues music
games-lbit.listserv.games-lComputer games
railroadbit.listserv.railroadRailroads and trains
scuba-lbit.listserv.scuba-lScuba diving

What's in a Name?


Text goes here.

Bitnet was started in the days when many universities had large IBM mainframe computers. In 1981, two researchers, Ira Fuchs at City University of New York and Greydon Freeman at Yale University, were discussing the Network Job Entry (NJE) protocol that was available for IBM mainframes. They decided that NJE could be used to connect computers over a leased telephone line, and they figured out a way to do so. Although they didn't know it at the time, this tiny two-computer network became the nucleus for what was to become the largest academic network in the world.

In other words, Fuchs and Freeman created the connection because they happened to have NJE. So, for this reason, they named their network BITNET, meaning "Because It's There Network". Later, this evolved to "Because It's Time Network".

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