We’ve been opening new Stack Exchanges left and right on a variety of topics. In almost every case, the Stack Exchange appears to duplicate the content of an existing community. For example, our WordPress answers site (now in beta) covers the exact same material as WordPress.org’s existing forums.
This is nothing new to us at Stack Overflow, which purported to cover the exact same material as hundreds (if not thousands) of other programming sites. There’s no rule that says that there needs to be exactly one Q&A website per topic.
There is, however, a compelling case for the Stack Exchange technology. WordPress.org’s forums don’t have voting, so you have to read through every answer and decide for yourself which one might solve your problem. They don’t have reputation, so there’s no way to see whether you’re getting an answer from someone who knows what they’re talking about. They don’t have wiki-style editing, so collaboration is impossible. You have to log on to ask or answer a question, so the burden of participation is higher. Stack Overflow is simply better than traditional forums, which is why it largely replaced proprietary forums. I remember hours of discussion with John Resig and the folks at jQuery who couldn’t decide whether to replace the jQuery Google Group with a forum or with a Stack Exchange. Ultimately it didn’t matter that much, because most of the jQuery Q&A activity happens on Stack Overflow anyway.
One day, the features that are standard on Stack Exchange will be copied everywhere. Until then, we’ll keep churning out new sites.