Pipl.com is “easily one of the best people-finding resources out there.” Like several rival services, it uses a Web-crawling algorithm that allows it to pull information from a zone of the Internet that Google and Yahoo don’t see—searchable databases like court records and marketing lists. It excels at delivering the most relevant hits.
123people.com works well too, but “based on our experience, the site’s robots can’t crawl quite as deep as Pipl’s.” You do get “a good bit of information” for free, though, and further detail only costs a buck or two. A detailed Pipl search can run to $40.
Spokeo.com is particularly good at sifting through geographical information, even roughly locating the search subject on a neighborhood map as part of its free service. A $2 fee gets you “pretty much any info you need.”