Long Time Lost is a free "service" that allows you to create a "search" for someone you lost touch with. That "search" is then indexed by Google (and other search engines) and then when that person you are looking for (or someone who knows them) does a "Vanity Search" (the process of searching for one's own name on Google)... they find your "search" and can respond to you and reconnect. All information is handled through the system so your private information like your email address isn't out there on the net.
It's new, it's Web 2.0, it's powered by Google, it's Ruby on Rails... and it's FREE... so check it out.