Graph Search Optimization (GSO)
A subset of the more general search engine optimization (SEO) that focuses on ways to optimize the content of a company or individual in an effort to improve their search results on Facebook's Graph Search.
While Graph Search is still in private beta and Facebook has not yet detailed the algorithms and formulas used for Graph Search, Graph Search Optimization (GSO) has already become popular among marketers and companies looking for the latest edge in boosting their search engine rankings.
See also Five tips for Driving Search Engine Traffic and How Do Web Search Engines Work in the Did You Know…? section of Webopedia.