We knew that refurbished iPhones have their previous owner's data on it, but how do you protect yourself when Apple won't go through the trouble of wiping phones out before passing them on? By unsyncing everything, then loading it up with music and videos until the phone is full to overwrite the old data that was there. Does this work? We thought the contacts, calendars, SMS and phone calls were stored on the OS partition, not the media partition where videos and music files go.
If you're sending in your iPhone for repairs at the Apple Store because it's broken, you might not have the option of wiping your data like this. It's not really THAT great a method either, but will be able to stop the next owner from casually recovering data. Basically, just run a restore and hope the next guy who has your phone isn't nosy. [Securosis via TUAW]