Not so surprising when Google would have to explain to the carriers why customers are dropping down to the bare minimum number of minutes on their plans because they can dial for free through Google Voice. I know the carriers make a lot on mobile data, but people still pay for extra minutes, and they'd lose that revenue. I reckon they're probably not thrilled about GrooveIP, either, but that's from a third party, so they don't really have the same kind of leverage they'd have with Google.