I know this would freak me out. Quoting this Me-Fi post:
Reason magazine uses individualized data to give its subscribers a ‘1984’-style surprise. The idea surfaced a year ago at a cocktail party: What if you opened your mailbox to find a national magazine with your name on the cover and the headline “They Know Where You Live!” — under an aerial photo of your house? And what if, when you turned the page, the editor’s note and the advertisements included details about your neighbors?
Full Story (requires registration, but you can get a user/pass here).