Google has provided additional information to the FCC's regarding Google Voice. You might remember that Google already responded to FCC's questions about Google Voice and why a mobile app for it was rejected for the iPhone.
This time, Google Voice is responding to concerns raised by AT&T about restricting calls to select area codes, something telecommunications carriers are prohibited by law from doing.
In the most recent letter to the FCC, Google said they're not a telecommunications carrier because their service is not open to the public and it's free. Indeed, Google Voice is available by invitation only and is free - for the most part. Still, the public can request Google Voice invitations and they must pay for international calls. Google says, though, that international calls only make up 4% of calls placed through Google Voice.
Instead, Google calls itself an information provider:
Google Voice constitutes an "information service" under the federal Communications Act, 47 U.S.C. § 153(20), because it offers users "a capability for generating, acquiring, storing, [and] transforming" information of the user's choosing. The Google Voice number is a personal number for managing the user's connectivity in one place, and it is not associated with an underlying telephone access service.
Google maintains that Voice as a web-based application, but stresses it's not VOIP.
Google Voice is a Web-based software application. It is a single, integrated unified messaging and call management offering that is completely distinct from the user's existing telephone access lines/services.
Google's strongest argument is that you can't simply sign up to Voice as a telecommunications provider. Instead, Google Voice is used to manage the telecommunications services you're already signed up to.
Importantly, prospective users of Google Voice must subscribe to one or more traditional telecommunications services to be eligible to create a Google Voice account. The Google Voice system will require that a unique US telephone number be verified before an account will become active.
What truly looks to be the problem is that Google Voice is a combination of information and telecommunications services, which doesn't fit existing (and now outdated) descriptions of providers as set by the FCC and Congress. Ironically, both AT&T and Google probably have similar goals here: to bring government regulation up to date with how technology has progressed.