My FF keeps crashing after hours of use & when it does I often get a "windows out of memory error". Often I notice it's eating up 500 M or more of memory after hours of use. It seems when using Facebook or Yahoo it keeps eating up memory & doesn't free it up till I close all browsers. This problems has been going on since FF 4.0 or earlier & I'm surprised this hasn't been fixed. I've contacted FB & yahoo & they say it's FF so we need proof for them to address the problem or better a way for FF to deal with it so it doesn't happen with other sites. I tried FF safe mode & it still happens.