ahem...

December'07 issue (security dedicated) of USENIX's bi-montly login; - straight in Rik Farrow's editorial named "musings", there is stunning quote: "Deeper inspection of the iPhone revealed that all applications run as root, evidence either that the iPhone was rushed to market or that Apple programmers are extremely lame. I know the second conjecture is not true, so I must presume the first."

From Wikipedia "Root user" article:
"It is never good practice for anyone to use root as their normal user account..."

Now, as you were warned... So, you've said that you want to go and buy that iPhone?