the debate between free publicity and content ownership is a huuuuge issue
some companies get it, others don't. remember how bad the wwf and marvel were a few years ago, taking down all those fan sites? matt groening/simpsons stuff was just as bad.
typically, the most tollerant situations are with movies, as film "success" is more and more solely dependant upon box office numbers; specifically opening day. if you have a few thousand fans out there that wanna spread around your word with pictures, clips, or games or whatever, generally studios are all about that.
i really don't know why the iron man stuff is so different.
my best guess is there is a movie coming out in a week or two that was to be hyped for also including the trailer, and thus the studio wanted to control its distribution to maintain the trailer's clout. but, really, who knows. could just be a douchebag decision.
