I have to disagree slightly with that.paulmustang1 wrote:I am sure they would love to sign for all their fan's but they wouldn't be famious anymore because it would just revolve in signing autographs and not doing what they are famious for.

I don't for one minute believe that if a celebrity put his or her mind to it, and answered their mail personally, even if they got a thousand letters a week, that they wouldn't be "famous" anymore because they signed things and didn't have time for anything else.
How many times could you write your signature in an hour? And if you have a really great secretary (which I'm sure most of the big stars do have), who can file and docket each requst, so the celerities don't even have to open the envelope or even bother sealing them, and everything is sorted out for them, then that would be even easier and quicker. And even if you don't have the greatest secretary, I still think setting aside an hour a day (or even longer when they're not doing anything in particular) will help to get some of the requests down.
That's just my opinion though. I'm not really one of these people who dimiss signatures as not being genuine unless they see them being signed in front of their eyes. If it is generally agreed by people that Mr. X signs things himself, I am happy with that.