15. Can I send attachments to my lists?
Short answer: Yes.
Long answer: LISTSERV will happily pass just about any kind of attachment through the list that you can think of without comment. The problem you will undoubtedly run into is more along the lines of whether or not your users all have mail clients that can deal with the attachments, either from the aspect of being able to read and decode them (some attachment formats are proprietary) or from the aspect of how large they are (some ISPs limit the size of an individual piece of incoming mail). You also need to keep in mind whether or not your subscribers really want to receive attachments; many do not.
It is usually best to place large files on an FTP or Web server somewhere and simply provide a link to them when you post to the list. Most users on POP dialup accounts will thank you for this, since they won't have to unexpectedly download a large file that they may or may not really want.
LISTSERV does have an "Attachments=" list header keyword that can be set to allow or disallow either all attachments or a subset of certain MIME attachments. Please see the documentation for "Attachments=" for more information.