Huh. That's an interesting question. There are, obviously, certain kinds of forks optimized for certain kinds of food, such as the cake fork. Your question made me read the (German) Wikipedia article on forks. It lists at least ten kind of forks (including those which are used simply for serving meat and the like). Also, it points out that the relevant edge of the cake fork is on the left side, which, I suppose, is optimized for right-handers. Are there "flipped" forks for left-handers, I wonder?
Relevant:
http://xkcd.com/419/Also, regarding
what, hundreds of years?
It says that at least the ancient Romans used forks, but mostly for serving, not for eating.