Have you heard of Google Voice?
Here is an interesting articles stating 5 reasons why you should use it, and 5 reasons why you should think twice:
http://www.pcworld.com/article/16742...ink_twice.html
For the privacy reason alone, I don't think I'll use it. Plus it seems like a lot of "setting up" is needed.
People like easy stuff. Phones ready to go, putt the lasagna from the freezer to the oven and forget about it for an hour etc....
I don't see that being a huge hit for now.