This is a little late, but my gmail was hacked as well. The very day I first installed the duplicate remover application for N900 and probably about the same time this thread was started. I still have no idea if that was the reason - figured I'd hear about it if there were others. I just missed this thread.

Other candidates for the security breach are Draugr.de -> gmail transport for using MSN over Gtalk.

Nuevasync for getting exchange -> gmail support on the N900.

I didn't raise an issue about this, since I had no idea of knowing where the breach happened. It would be interesting to hear what similar services other victims of hacking have been using.

Hats off for Gmail though - the person who hacked my account used a script to send a single (russian) url to all people in my address book and Gmail stopped it because of suspicious behavior. The mail actually went into the "sent items" box of my gmail, so it somehow was sent explicitly through my gmail.