Okay, after spending a day reading news and what have you on my ipad, I decided to sync up and see what happens. I still have 15,719 files in my backup folder. Ipad is still backing up to the same folder. The backup took 9 minutes. Of the 15,719 files, 93 files amounting to 6.6mb were modified. The files were mostly news app files. So it appears, if your backup is corrupt, or has never been run, or is new, or if you have added a lot of new apps, you are in for a long backup. But once its done, itunes just backs up the stuff that has changed. Hope this helps answer some questions.