I got this from a metafilter discussion. Is this something you have noticed? I have never seen it before.
A few examples:
people think they are writing to chatshow host here
people think they are applying to be on a show where old cars are restored here
people think they are writing to Bill Gates here (this is one of many)
people think they are writing to a porn star here(particularly choice are the gallant gents who call her a 'dumb slut')
EDIT - I feel guilty about mocking some of these people who are quite young or tragic, so sorry. But read the thread about the car show, some of those are hilarious.