The Elder Scrolls V: Skyrim, Call of Duty: Modern Warfare 3 and Battlefield 3.
Those 3 games really pulled everyone away from wL forums.
Like I said, they'll be back. They always come back.
Some people leave for games, some people leave because theyre bored of the forum, and some leave because they find another community. wL's always has its slow days every once in a while.