In December 2005 all tribes that had once upon a time been designated as "mature" in content were forced to become private and stopped being publicized, which meant that they would not show up in topic-searches. Private tribes may continue to have explicit content without much fear of censorship, except possibly from within, so choose carefully whom you let in to your tribe.

Because private tribes are nearly impossible to find without outside referrals, this tribe was established as a site for posting the names of tribes with explicit material of particular interest to men who are sexually aroused by men.

http://tribes.tribe.net/gaysextribesinfo