I would keep the listserv. I've seen this discussion a couple of
million times. There are listserv people and there are forum people.
It costs nothing to serve both.

And sometimes you need the relative privacy of a members-only
listserve. There's an anti-mtb site that uses a quote of mine (out of
context, of course) that I made on the IMBA public listserv 10 years
ago. There are people like "Vandespam" who are obsessed with their
hatred of mountain bikes and troll public sites to pull fodder to
feed their pathology. A members-only list allows you to have
discussions under the radar. It can be infiltrated and you have to
assume it is, but it's still a lot less public than a Website.

A listserve for members provides added value. We have a lot of people
on TucsonMtb.com who like SDMB but don't join. Mountain biking is an
individual sport and it attracts a lot of people who by their nature
aren't joiners. Add to that the people who got their nose out of
joint at the club, the cheapskates and the procrastinators and you
have about 80% of the mountain biking community.

--mark