For quite a number of years (basically since I've had the internet), I have seen many profiles- in Yahoo Groups, Twitter, Facebook, Myspace, everywhere!- of celebrities. Except they are usually not celebrities, but 'regular' people pretending to be that celebrity. Even dead ones! Now some are humorous, a parody of sort- and that's okay but to actually say "yes I did that movie" is going too far. I do understand obsession, believe me I do as I do have quite a few of my own, but I also have a limit.
If you are a fan: then do a blog, a website, fan page on Facebook or Myspace or Twitter to post news, pictures, whatever you get your hands on. You can display your love for them that way while being yourself. I can live with that.
But to pretend you are Marilyn Monroe? Or Princess Diana? That's going to the extreme.
Another thing is character profiles. People who actually make twitter or facebook or myspace or whatever as a character from a TV show or movie. These people actually pretend to be that fake character. Easy does it now! It may be a little cute at first but if you keep going at it, then something may be wrong with you
It's unfortunate that celebrities do have a hard time- when they have twitter they have to be 'verified' or post a picture of themselves with their profile so that normal regular people wouldn't have to fall into that scam/trick to think that they're chatting with Jeremy Piven when they're actually not. It's sad really.