Gmail has become the de facto e-mail address of everyone. Most people now use gmail e-mail and we therefore developed an extensive database of gmail e-mail addresses and associated owners so we could let everyone search true owner of any e-mail account. You no longer have to wonder where you got the email from.
If you are trying to lookup a loved one, where they currently live and what they have been through (places they have worked, addresses they have lived at, relationhship statuses they have maintained), then simply search them on PeepLookup. We recommend you start with your own e-mail to see different kinds of data points we provide so you understand how it works.