Stack Exchange network consists of 182 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.
Q&A for work
Connect and share knowledge within a single location that is structured and easy to search.
I like "Ask Question" and "Tags" features in StackExchange, who can tell me that if "StackExchange" is created with sharepoint?
Stack Exchange and Stack Overflow are not created with SharePoint. They use a custom ASP.NET solution.
For more details of the technology stack see meta.stackoverflow.com.