Usenet is Usenet, E-mail is E-mail. Though
Usenet is often found on the Internet, it
isn't always. E-mail is also found on
networks other than the Internet, which might
be different yet from Usenet access.
If your friend can e-mail someone on the Internet,
most likely they can join most e-mail lists.
Some mailing lists can be found on Usenet. Sometimes
in groups such as BIT.LISTSERV.listname
/Pete Weiss at Penn State