Auto-syncing updates the file and directory lists, but doesn't copy all of the files over. I know this because the folders I have linked have way too much to copy over, literally hundreds of gigs. This is different though if you choose to download the contents manually.
Sent from my DROID RAZR using DroidForums
agreed but if you do not watch it it will eat up 300+ meg worth of data in short order. i as well have tons of gig worth of data on my pc and after investigating why my phone downloaded tons of data when the phone was idle was because of the music app that was sync'd with motocast. i do not like apps downloading tons of data withou me knowing. this also ate up the battery.