Though I do not know what technology they use (I don't think it has
anything to do w/ L-Soft's products), The Chronicle of Higher Education
has a subscriber-only e-mail newsletter that one can join, using hardcopy
publication address label info which gets plugged into the HTTP
subscription form.

A LISTSERV technique that we have found very useful is to
DEFAULT-OPTIONS= REVIEW (for a SEND= PRIVATE, SUBSCRIPTION= OPEN,CONFIRM)
discussion group of wide-area colleagues).  As time permits and
appropriate, we follow-up with a


QUIET SET listname NOREV FOR subscriber/poster

This "keeps out" the mid-nite spam/scammers from subscribing and
posting.  Yes, there is some cost to the list-owners, but for the scale
of that operation, it "worked."

YMMV


/Pete unplugged but not disconnected
Retired PSU