Facebook (FB +2.5%) will make Graph Search available to all of its U.S. users today, according to multiple reports. Graph Search, announced in January to much fanfare, gives users the ability to make queries based on linked parameters (e.g. a search for Italian restaurants in New York liked by friends). Bing (MSFT) will act as a fallback option. Though some see ad-revenue potential and an indirect threat to Google (GOOG), questions still exist about privacy, the user learning curve, and how useful results will be given how much content is restricted to a user's friends. Facebook's efforts to increase public sharing could make Graph Search more valuable in time.