Twitter has a people filter on its search, like Facebook does, as well as an advanced search page.
You can even search for tweets to a particular account, which could be useful if you're looking for someone who loves @ladygaga.If you can connect with an individual who is somehow linked to the person you're looking for, a lot of social networks will instantly throw up a list of other recommended contacts, which may lead you closer to whoever you're seeking out, or at least give you clues about how to track them down."Even if you don't have an account, chances are your family or friends do," says Giglio."Even though it is possible to delete content from online profiles or cancel an account, the data is already shared and could be saved by other users or by the entity or service being accessed." If the Google trail is dead, try alternatives such as Bing and Duck Duck Go, then try search engines that go deeper -- Web Crawler, Dog Pile, and Monster Crawler are three examples to try, and of course you have the Way Back Machine that can turn up pages that have since been removed from the internet.Pipl is another engine recommended by our experts, and goes beyond the results you'll get from standard search engine, as well as adding useful filters for location and age.