Stack Exchange

Stack Exchange is a growing site of Q & A site. It has diverse sites ( 46 to be exact ) under it for different topics, such as, Stack Overflow, Super User, etc.

This site has recently grown very quickly, and now, even Google is paying quite the attention to it! Google is indexing Stack Overflow at 10 times per second. This means that Google's robots, which crawl the web to give you search results, are visiting Stack Overflow 10 times per second. This level of attention from Google's algorithm is a pretty impressive testament to how active and big the site is now.( Source : Business Insider)

All questions on Stack Exchange are expected to be objective and have concrete answers. Stack Exchange is not a place for conversation, opinions, or socializing. Stack Exchange’s focus on professional communities and this “Just the facts, Ma’am” ethos results in over 90% of questions getting great answers, often stunningly quickly.

In my opinion, the big divider between this site and other Q&A sites so far is that this site has a lot of sites under it with different topics and experts on them, which makes it easier to get some specific answer on certain topics.