That's right. MANDATORY. Refuse to put trophies in your game and you, developers, will be SHOT. Your families, BILLED for the expense. Or...at least, Sony will be very cranky with you. Because, come January, all new PS3 games must have trophy support. No ifs or buts. So no more patching, no more developer ambivalence, no more inconsistencies. Not sure why Sony didn't do this from the start, but doing it now, at the middle, is better than never doing it at all.
PS3 Trophies to be mandatory from January 2009 [Videogamer]