With well over seventeen thousand registered members and growing, MetaFilter
is hosted and operated by a guy named Matthew Haughey
who's pretty cool allowing everyone to play in his sandbox
so long as you don't piss in his swimming pool
It's a collaborative weblog of sorts, but allows registered members to contribute a link or a comment at any time, thus filling the webspace up with stuff that some people find interesting but other people bitch about incessantly. It's kinda like what newsgroups could have been if people actually gave a shit about them. It's really neat, because instead of just reading a weblog made by one person that has all of that person's thoughts and opinions in a way where no one else can rag on him for thinking for himself, MeFi allows people to say what they want and then immediately be subjected to reasons why they should have shut the hell up in the first place.
MetaFilter started July 19, 1999 with a link to cat-scan.com which inspired over 150 responses. It's received awards, been mentioned in magazines, and has won the admiration and loyalty of thousands. No really. MetaFilter's a lot of fun, and every once in awhile (at least daily if you pay attention) you actually learn something.