There's a whole bunch of stuff that keeps me coming back. The board is great cause it's well moderated and does't have problems with immature people posting 'you suck' messages. It's also wellpopulated by some seasoned guitar players who really know their stuff and are willing to answer any questions put to them.
The best part though is the main section with the amazing hosts and tricks sectios. Most other sites that give lessons are kinda pathetic, geared to beginners or only have relatively few things worth looking at. Guitar tricks has thousands of lessons with sound files, with a great majority of them aimed at advanced players and the unreal part is that it's totally free. Another thing I like is that the interface and web design isn't loaded up with tons of memory hogging graphics. I can sign on with a 10 year old computer and still access everything on the site.