There seem to be two issues here. The first is that reading these long things takes time; while this is an issue, it seems to have been discussed pretty thoroughly at this point. The second, and more troublesome though less-talked about, is that these long descriptions actually screw up roleplay. There is no way I should know your "mother died at the age of two" just by looking at you. Good roleplayers will (hopefully) understand this and ignore these lines. "Problem solved," yous ay. However, there are a few issues that persist:
1. Up and coming roleplayers may not know how this works. The result will be some awkward roleplaying... best to be avoided. This is the least of the problems, though.
2. People forget. A good roleplayer may think, "I heard her mother died somewhere, forget where, but I did hear it..." and assume that the knowledge is in-character.
3. People are influenced unconsciously. If your character acts like a perfectly nice person, but has, "A slick double-dealing assassin" in his profile, even the best of roleplayers will treat him slightly different, though they may fight not to.
Out-of-character knowledge is BAD. There is no getting around it. Please, do not put histories in your character descriptions. It's been driving me nuts forever. I'm glad to see other people share my opinion.
