But even this system wasn't perfect. To use all of Google Voice's features with your main number, you still had to own an entirely separate number through your wireless carrier. With Project Fi, all these capabilities are built into the wireless service. In a way, it's what Google Voice should have been all along.
Where Fi goes now
Interesting as Project Fi is, Google paints it as merely an experiment, not a direct assault on the mobile broadband business. This could just be diplomatic posturing — after all, Google can't really take an axe to wireless carriers when it's relying on their networks — but it's more likely that the company is trying to wield its influence indirectly.
Imagine, for instance, if Google could convince other carriers to support the cloud phone number, letting users access their calls and text messages through Google Hangouts on any device. To sweeten the deal, perhaps Google could even let carriers tap into the same network of Wi-Fi hotspots that Project Fi will use.
This isn't as crazy as you might think. After all, Google's Nexus phones work in similar fashion, demonstrating the benefits of pure Android to users and the industry. It's taken a while, but phone makers are starting to get it. In time, maybe wireless carriers will as well.
Sign up for CIO Asia eNewsletters.