Left 4 Dead 2
It's not just you mate, I've been trying to get the auto updater to work since it was introduced.
I've been referred to and followed the instructions over and over...but just no results at all. You hear the "Trainer Activated" voice when you start up the game but I can never get anything to actually activate. It never crashes or locks up, it just doesn't do anything. I keep scanning the boards for a solution but just keep finding those that have the same issues.
I wish you the best of luck!
A 5gig patch is coming down the pipe this morning, so we'll just have to have some patience.