Facebook just unveiled a new search function that people can use to search for all kinds of things, including locations and interests. That includes local businesses like restaurants and dentists, Facebook engineer Lars Rasmussen said at the search-product unveiling today at Facebook's headquarters. That's spooked Yelp investors, who have sent the stock down 7.75 percent today. This is a very interesting battle. Yelp has roughly 80 million active users, a fraction of Facebook's audience, and has only recently started to expand internationally, where Facebook is strong. But Yelp has an ... Read More