PS3 gamer here.

I can't answer this in super-technical terms, but it has something to do with the game not resetting itself properly. There's a few things you can do to counteract file size
> don't leave stuff laying around everywhere. If you're in the habit of playing the big, burly Nord (whatever) who crashes around everywhere and knocks plates and silverware around, this is apparently supposed to be not good for file size, as the game has to now remember where everything has been moved around to.
> sometimes (if I feel like it) I've been storing random items left lying around into dead bodies. Since dead bodies do respawn, this means all the objects stored in those bodies will also respawn. This means the game will need to "remember" less overall.
> if you go thru a door or a gate, close it if you can.
>This one is most difficult for me:
Don't explore excessively until the new patch is out. Don't take on quest after quest, etc. And once it's out, let's see if it helps those players who are having the most problems.
> save often.
>turn OFF all the autosave options (wait, sleep, and travel)
> I've never had any problems with my game, as I've been proactive since I first heard about the issues starting to happen 3 weeks ago and my largest gamesave to date was 6.8 mb. But if you do have stuttering or lag or whatever, saving, quitting, and restarting is supposed to help. For a couple hours.