Ding-dong, Deals –– Facebook’s Groupon competitor for finding nearby bargains -- is dead after just four months. (Don’t feel bad if you missed out…it was available in only five cities.) Deals is a rare misstep from a company that seems to get bad press only for occasional privacy-related dustups. Despite them, Facebook has done pretty well since launching in 2004. Here are five of the top ideas that have earned the House of Zuckerberg over 750 million users and one of the top spots in tech.