I'm a member from way back when it used to be www.guitarwar.com
It gets a bad rap around here and a few other forums I've seen because "music is not a competition." That's true, but I think the competitive side of the site gets played up a bit too much - sure, it's a competition, but it's a competition the way head-cutting at your local blues jam is - it's a friendly competition, more about, "hey, show me that lick, that was awesome!" than it is about determining who the best player on the site is.
I can tell you that I learned a LOT about both playing and recording technique from that place, and that I wouldn't be the guitarist I am today without getting that chance to pick the brains of some seriously good players, and without getting exposed to some of the artists that I was introduced to on that site (both members and "hey, that run at :36 sounds a bit like something Vinnie Moore might do, if you're not familiar with the guy's stuff check out "The Maze," I bet you'd love it").
And, the camraderie at that place is great- there's the occasional dick, but most of them quit after a few months, and it's like a big musical family.