Last year, AOL inadvertently exposed a data set that contained over 20 million searches performed by hundreds of thousands of users. It was only exposed for a brief while, but in that brief period it was copied all over the internet.
The records are fascinating to browse, and there is even a site dedicated to characterizing people based on their search activity. Like the person characterized as a "pet owner, parent, and possible animal fetishist." Someone figuring out how to commit murder. And my favorite, someone who is searching for their computer.
It is fun to browse. And yes - there are some real sickos out there.