I'm pretty sure the idea is that if your at work and your worried your phone might right but you don't want to mess around changing settings you can just turn it over and it won't ring until you turn it over again, basically toggling the silent mode from on when face down to off when face up. That's how I understood it. I just tried it on my HTC Desire HD, so I rang my phone and it started ringing, your suggestion that it goes silent if you turn the phone over didn't hold up, nothing happened, it was ringing, I turned the phone face down on my table but it kept on ringing. Also when its face down and the phone is set to ring and vibrate it still rings. any ideas? It should be silent when face down, I've seen people complain that this happens and they DON'T WANT IT TO so it is the desired functionallity, just need to know how to activate or turn it off. thanks