Hi. I'm group leader of Nottingham Perl Mongers (http://nottingham.pm.org/) in the UK. I can be found over at PerlMonks (home node = http://perlmonks.org/?node_id=195331) usually when I should be working!
We run Apache::MiniWiki for our entire site (http://www.tecspy.com/wiki/) and find it pretty good for our needs. All of our editors are group members and all authenticate with the htpasswd technique for editing as mentioned by jammin in WikiLogins. We also use the robots.txt technique as we seem to get a lot of bots for some reason. I'm testing a few extensions that I've made to MiniWiki - I think I left some info under FeaturesWantedInMiniWiki.