The Dragonsfoot Forum is 9 years old. Founded in 2002, Dragonsfoot is probably the best known forum for discussion of TSR era D&D rules. During the time when Edition Wars were raging all across the the Internet, Dragonsfoot became the shelter for people who did not want to move into WotC's (then) brand new version of the game. While sometimes being accused of being a haven of paranoid grognards, it is an amazing source of information about the early days of gaming and the older rulesets. You might have to develop tough skin to participate in the most heated discussions there, but all in all I am glad that a place like that exists! :)
For one this is where I met some of the key people involved with the Comeback Inn!