just how explicit can we get in the photos we post?

Per the FAQ on the forum: We have been adjusting the rules as the site and the membership has evolved. It is time now to solidify the rules on what types of photos are acceptable and what is not. Topless has always been acceptable (and even encouraged!), and most classy nudes are fine in theme day posts and friends or private albums. The graphic spread-em shots that would embarrass a gynecologist and sex shots have started to creep onto the board now, so we are going to have to clamp down on that. If members would like to share those types of shots, by all means, exchange emails or post them to your private groups and password-protected albums. But please keep them off the main wall.

Additionally, website and other revenue generation solicitations (including watermarking or branding photos with a website) are not allowed on the main wall. They are fine for your private groups, but Tor and MS are the only entities that should be posting ads on the main page.