I originally joined LiveJournal for gaming-related reasons: to post writeups of games in my several roleplaying campaigns, read writeups posted by my players either for my campaigns or for other campaigns that they run or play in, join and contribute to communities created for these various campaigns, and otherwise exchange campaign-relevant information. That's largely gone by the wayside, as only about one of my current players is active on LiveJournal. Nonetheless, about half my posts seem to be about games I run, books I write for Steve Jackson Games, or more general gaming-related topics.
I'm running two campaigns: Tapestry is my first venture into historical fantasy with multiple intelligent races in an invented world, with characters who are seafarers engaged in exploration and trade. World Class is inspired in genre by The Avengers and the rest of the Marvel Cinematic Universe; its big gimmick is that the player characters are the world's only major superheroes and define the concept of what a superhero is for their milieu. I'm also playing in one campaign, The Road to R'lyeh (Call of Cthulhu: encounters with Mythos entities in post-WWII Seattle and environs), run by koressa.
I also post philosophical, literary, and political comments and random thoughts and jokes. Larger pieces often appear at http://www.troynovant.com/ .
My journal is named to commemorate my regular 'zine in the APA Mutations, which I ceased publishing in January 2005 with monthly issue 253.