Check out this screengrab of my Task Manager showing the Firefox browser eating up 1.4 Gigs of RAM only seconds after I opened it. All I did was go to the MLB.com’s video page and only a single tab in Firefox is open:
I’ve seen this on multiple computers with the same versions of Firefox/Firebug, and while a few others have reported similar issues, I don’t think I’ve heard of a report of such an extreme case and even less fortunately, no report of the root cause nor a forthcoming fix.
For the time being, I’m reverting to Firebug version 1.2.1 which is much less memory-hungry. I suggest you do the same.