Have you recently learned that your great grandfather's sister is still living? Have you lost touch with an aunt or uncle who may be able to fill in some genealogy blanks? If so, there is a unique search engine that may be able to help you locate them.
Pipl is a specialized people search. It is able to search the deep web, places traditional search engines can't go. It can find email addresses, addresses, phone numbers, social networking profiles and more.
I searched my own name (both maiden and married) and it found my current phone number and address, two of the towns I previously lived in, where I went to high school, a handful of email addresses (one of which I set up over 10 years ago and no longer use), and a couple profiles on social networking sites. Everything was neatly organized in sections.
I do want to note that some of the results Pipl finds require a subscription to access. For instance, some of the email addresses it found for me were in the records of a pay site so the results did not spell out the full email.