Gay-Board.org is a gay porn forum that launched in March of 2011. Word on the street is that another popular forum (I'm not going to say which because I don't know the full story) had some admin issues and the users weren't being taken seriously. A mass migration occured and some people headed on over to Gay Board as their alternative of choice. Today, it boasts over 1.7 million posts contributed by more than 100,000 users.
There are three main areas: videos, images and 'special'. Sub-sections for each category exist, so if you want videos of BDSM or amateur pictures, there are relevant areas to come across exactly that. Gay-Board.org also has a place for users to submit their own content, so if you fancy sharing yourself on a porn forum with thousands of users online at any one time, go ahead and do it!
Gay Board is ran by a gay porn enthusiast that wants to make it easy for fans of gay porn to share their love of X-rated content. I do recommend you check it out and stick around: this is one of the better boards out there.