The reason for such a list is to deal quickly with questions that come up on a regular basis, especially in groups with a particularly high readership. Not every group has a list, and some groups have more than one; it depends entirely on the breadth and popularity of the subjects being discussed within the group. In general, if there are questions that come up more than once or twice a month, they are candidates for an FAQ - people will tire of answering such questions very quickly.
Examples of questions that might be put in such a file for a very general computer group could include
"When is Windows '95 being released?
How can I get access to the Internet in <location>?
What does FAQ stand for?
Groups about more specialised subjects would naturally have more specific questions.
Typically FAQ files are posted to other groups as well as those for which they have been specifically constructed.
news.answers is the group where most FAQ files can be found, with
comp.answers etc. having FAQs for their specific hierarchies posted. This means that, if you want an answer to a question and you're not sure which group would be appropriate, you can check the FAQ files in the appropriate hierarchy to see whether your question has already been answered many times before. If not, you may be able to gain some idea of which group might be appropriate for your question.
FAQs sometimes serve another purpose; if you need a brief introduction to a subject about which you know very little, the FAQ file for the appropriate group can provide a very useful potted introduction to that subject, answering many questions that a non-specialist would be likely to ask. Since the files are widely available, it can be easier than visiting the library -- although if the subject of your interest is very esoteric, it is unlikely that questions about it will have been asked sufficiently often for an FAQ to have been compiled.
The FAQ files are generally archived in various places around the Net so that people can consult them without needing to wait for the next scheduled posting. The most comprehensive collection can be found at
ftp://rtfm.mit.edu/pub/usenet/, which collects all of the FAQ files which are posted to
news.answers; other copies are scattered around the Net, often at sites where there is other information on a particular subject. For instance, since Herald Information Systems is now hosting the GENUKI list (see the article appearing elsewhere in this issue), we have a selection of FAQ files about genealogy; we also mirror some FAQs about South African wine, and more which relate to other mailing lists run from this site.
Perhaps the most surprising thing about FAQ files is that, almost without exception, they are compiled and maintained by volunteers. There is no charge to download them from the archives where they are stored, although they are generally copyrighted against unauthorised commercial use (for instance, if someone published a book containing all the FAQs so far compiled). As such, they provide an extremely valuable service to Net users.