This happened to my best friend last night and pointed me to this link when he did some research. Just passing it along.
Originally posted by ArticleUnfortunately, gamers eager to sample the cel-shaded beat-'em-up were in for a very nasty surprise. That's because the demo contained a glitch that will erase all saved games on the memory card or cards currently inserted in the console.
no one cares but: I preordered Mod Nation Racers! Hope it's actually as good as the hype. Also, been playing the multiplayer portions of Uncharted 2 online the last week and the co-operative missions are actually really fun.