The Freepers!
Membership: right
Simple but effective blog layout with comments posted on daily news items. Militantly territorial community, impatient with strangers, particularly left-leaning ones, but very active community. The "Freepers" are notoriously aggressive in print. If you're not ultra-conservative and you're aching for a fight, you'll find one here. The site excels as a breaking news source as well. Just know that you'll catch hell from the locals if you aren't ultra-conservative or libertarian. You've been warned.
***********************
Heh.
Democratic Underground
A traditional forum layout. Needless to say, it's easy to get lost in the crowd at DU. The users are territorial too, guarding their particular categories/rooms. Most members choose one room and stick to it without venturing out into the DU no-man's land for fear of angering the locals. If the site suffers from anything serious it's bloat and an extremist membership. Dozens of different rooms, from General Discussion to Civil Liberties, Economy, Education, Science -- you name it. Site claims to have 104,221 registered users, and about 30 million posts since January 2001. Yes, that's huge.
The reviewer forgot to mention the liberal use of the F-word and other ugly words over at that site....and the hateful attack mongers and tin-foil hat wearing activists over who live there. Odds are the Reviewer is a duh-er.