Hi all, Upgraded the iPhone and recently sold the 3GS on eBay. The strange thing is that the eBay buyer had bought over 100+ iPhone 3GS and 3G according to his feedback and continues to buy. First thought that came to mind was that he "unlocks" the iPhone and resells it. But no, he only buys jailbroken/unlocked/refurbished iPhones at the average going price and don't resell. So I am a bit concerned. Is this guy "data-mining" all the previously owned iPhone for fraudulent activities? I'll be formatting the 3GS via the General settings but not confident if it will permanently delete all the personal information. Your thoughts are appreciated.