I would consider [Whozat] to be the most comprehensive people-search engine I’ve seen
SuperTicker writes about Whozat in his StumbleUpon review: “Whozat is a meta people-search engine drawing information from several social and professional networking sites as well as the web at large. Moreover, it lets you refine your search (indicate what’s “zat”) so to improve the relevance rank of your search results. See the Help pages.You can enter part of a name or even include keywords that would distinguish your person of interest from all the others. I would consider it to be the most comprehensive people-search engine I’ve seen.”