It's the 'personal fan' feature that was never fully implemented. It's supposed to measure ambient finger temperature, and if you have sweaty fingers, blows cool air over them.Sorta like the sd memory slot that was never utilized. I think someone's working on a patch for it that restores functionality.
have you checked the other port holes ? I think you're in for a nice surprise! :-)
I'm telling you. I sometimes feel air coming out of the earphone jack. Especially when playing games. It doesn't seem to be vibrating like a speaker would push air, but a steady flow like a fan when the unit is under load/playing games, etc. Maybe it's just warm air escaping. I dunno. And if for some reason the tp is using the earphone jack for ventilation, what's gonna happen if I plug earphones in? Is it gonna trap the hot air in???