From the about page:
Stack Exchange is a network of 130+ Q&A communities including Stack Overflow, the preeminent site for programmers to find, ask, and answer questions about software development. Founded in 2008 by Joel Spolsky and Jeff Atwood, the company was built on the premise that serving the developer community at large would lead to a better, smarter Internet. Since then, the Stack Exchange network has grown into a top-50 online destination, with Stack Overflow alone serving more than 26 million professional and novice programmers every month. The broader Stack Exchange Network has expanded to cover topics as diverse as Mathematics, Home Improvement, Statistics, and English Language and Usage.