Most of the time, when I get mail from the former residents of my apartment, I just toss it in the shredder. But occasionally I get something that gives off the "important" vibe (something from the IRS, packages, etc) in which case I turn to the internet.
There's something fun about tracking down a stranger on the internet at finding a means of contacting them, be it email or myspace message. Every time this has happened, the person has been very grateful of my snooping so that they can be reunited with their important documents.
Last week I had my first incident since moving to LA - a suspiciously important looking letter turned out to be a check for $130 for one of my unit's former residents. Lucky for me, she had a unique name, so google turned her up pretty quickly (though I did have to make a Plaxo account to get her email address). Anyway, it turned out she still lived in the complex, but in a different unit, and was EXTREMELY grateful that I'd tracked her down. I went over the next day and taped her letter to her door.
Today when I got home, she'd taped a little thank you note to my door, thanking me again and saying I could call on her if I ever needed anything. So nice! Physical thank-you notes are the best thing ever.
Anyway, it just goes to show that having all of your personal information floating out on the internet available to anyone with decent google-fu can lead to good, afterall.