TUAW Tip: Tell Gmail not to send your iPhone a copy of sent mail
Several of our readers have written in and asked how to make their iPhone stop sending them copies of their outgoing Gmail. Here's how. Go to Settings -> Mail -> (Your Gmail account) -> Advanced. Switch "Use Recent Mode" from ON to OFF. Be aware that the first time you do this, you may end up sucking a bunch of old messages into your iPhone inbox. (I had about a dozen old emails which shows exactly how little I use my gmail account.) It's a one time thing, though. After you get rid of those old e-mails by disabling "recent mode", your iPhone will stop sending you those outgoing copies.
Update: This option keeps getting weirder. TUAW reader digitalintrigue discovered that copies of outgoing mail sent from gmail's website still get sent to the iPhone although copies of iPhone-originated mail do not. I tried this out and confirmed the behavior.