This is what I keep trying to push at the company I work for. However, the advantages of opening up communication and adding transparency aren't easily measured monetarily. It also really scares the folks in marketing - the whole idea of letting people within your company speak on its behalf.

Granted, the company Im at does use Twitter and FB, but it's a tightly controlled communication channel that does nothing more than to give off the impression that 'we are a forward thinking company'. Which, sadly, we aren't.

I think it really comes down to the fact that so few companies are capable of adding that layer of objective transparency, because so few of them have nothing to hide.