Spinning "wheels" on Firefox tabs?

Nope... It basically means that you've run out of main memory, and you need to shut FF down and launch it again... FF has never really fixed their memory leak problems. If you look at the processes of FF, you'll see over time that the memory allocated to it grows over the course of the day. Really horrible about this. It's possible that the latest version of FF (at least on the Mac) appears to have addressed the memory leak situation. I haven't had a chance to observe the processes of FF at the end of the day, but it has behaved a LOT better than older versions, which would force me to "force quit" FF 2-3 times a day. Now, I don't get what I call "beach-balled" and froze up. It's a PITA, but go ahead and update to the latest and see if it solves your problem.