What are the main competitor sites to Stack Overflow? I'm aware of Experts-Exchange and several forum sites that I use for C#, however this question is more about sites that cater for all programming languages just like Stack Overflow and are not generic like Experts-Exchange.
Programming websites: daniweb, dreamincode, codecall, bytes, devshed, and codingforums off the top of my head.
general Q&A: Yahoo answers (ok for any type of question, not actually good for any)
Stack Overflow has nothing to worry about. I know that may not be why you asked the question, but its kind of an overwhelming fact. SO beats the crap out of every other website in terms of rep system, features, organization, traffic, speed, moderation, and questions per day. I've done a lot of comparison, and SO almost always wins in every test.