ENWorld is a d20 board, and more specifically than that, a D&D board. Hell, it grew out of Eric Noah's 3rd edition rumor site.
The only reason it appears to be a 3e board is because it's a D&D board, and D&D is 3e to the vast majority of people. Hell, see how quickly 4e became the topic du jour when it was announced? That is of course going to lighten up a bit as it becomes less "news flashy" and I predict 3e will once again reclaim the majority of conversation, but when 4th edition approaches it will just naturally shift towards and become 4e dominant because that's what the people who visit the boards will do.
Which isn't to say that there will be no place for 3e, anymore than claiming that there's no place for older editions right now.