Following a discussion about fan fiction with laloveskt, I decided to post this link to one of the best comics EVAR!
http://piratemonkeysinc.com/ms1.htm There is soooo much bad fanfic out there. There are characters which are clearly veeery thinly veiled attempts by the authors to insert themselves into their favorite stories. So if your character is Voldemort and Adama's secret love child, you are probably writing a Mary Sue. No one is that pretty, and that magical, and good with animals, and everyone loves them, and a super smart ninja jedi ! wizard, and they fart rainbow sprinkled kittens. Just...no.