Your Internet Consultant - The FAQs of Life Online

5.25. How are mailing lists different from Usenet newsgroups?

Answered by Dave Taylor (

The Internet is full of subtle but important distinctions between different types of data. One of the more subtle distinctions is how newsgroups differ from electronic mailing lists. When you consider that there are two main types of electronic mailing lists (those that forward to all members any mail sent and those that have a moderator who screens messages for appropriateness) and two types of Usenet newsgroups (moderated and unmoderated), the lines definitely blur.

There are two primary considerations for building and maintaining a special interest discussion group: control and dissemination. Why is control important? If you're a member of a discussion group you want to ensure that the information you receive is relevant and appropriate for the audience. That is, if you're involved with discussion of high-level physics string theory (or some other specialized discussion), there is an expectation of a certain amount of knowledge on the part of the participants.

Control is also a means of maintaining the quality of information in a discussion. The more narrowly focused a discussion, the more you might want to consider imposing some sort of controls on the group, either at the point when people join (for example, by sending a note indicating that there are certain expectations of knowledge or interaction inherent in the discussion) or when they submit information (by moderating the discussion). Both work for mailing lists, and moderation works, quite effectively, on the Usenet.

Dissemination is the other half of the coin: although it may appear that the Internet is free and infinitely powerful, that just isn't the case unfortunately. With the Usenet, only one copy of each article is present on any given computer, whether 100 or 0 people read that discussion. However, with a mailing list, each recipient gets an individual copy of the message. A large mailing list leads to hundreds of messages filling up mailboxes left and right! If you have 70 people on a single machine and they are all subscribed to a mailing list with 20 new messages each day, you're talking about 1,400 messages every day; the resource demands can be quite high. Expand this across thousands of systems and 10,000 readers, and it becomes clear that at a certain point it makes more sense to use a newsgroup rather than a mailing list.

The reverse holds true too: a Usenet group discussing 1967 Chevy Cameros is far too specific to be of interest to a lot of people, but it might make a nice 40-person mailing list, where participants can learn about each other's interests.

Rule of Thumb #1: If there are less than a couple hundred people interested in the subject, it will probably work better as a mailing list.

Rule of Thumb #2: If it seems as though there are going to be a lot of irrelevant or inappropriate articles in the group (either mailing list or newsgroup), assign or nominate a moderator who can screen submissions and just let the highest quality articles through to the readership.

There is indeed a blur between mailing lists and Usenet groups, and it's a healthy mix. Many times mailing lists will grow and grow as they become popular and ultimately spawn Usenet groups as the resource demands increase.

As I said, it's a subtle distinction and there are a variety of different factors that affect whether a particular discussion is best as a mailing list or newsgroup, but the most important ones are resource demands and dissemination of the material.

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