Earlier this week, Google shocked the world when they announced Project Fi. The announcement of them becoming a mobile carrier wasn't the shock, it was actually the pricing. It's essentially $10 per GB of data, although you do get a refund at the end of the month for the data you didn't use. But many were expecting Google to offer unlimited data, and that didn't happen. However, the service is still pretty revolutionary. The service runs on both T-Mobile and Sprint. As well as WiFi. So your Nexus 6 - yeah it only works on the Nexus 6 - will hop between WiFi hotspots, as well as T-Mobile and Sprint's networks automatically, you don't have to do anything. Which is nice, to not have to worry about switching from WiFi to LTE all day long.
So what about making calls? Well that's all over WiFi or LTE, basically it's all over a data connection. So no more using the old voice networks that most carriers are still using. Google has released a video showing how exactly it works. It's basically converting everyone to using Google Voice, through Hangouts. The second video that Google released was about checking data usage. So you can check via the data usage option found in Android, obviously. But you can also view your data usage through the Project Fi app - at least it looks like it's an app, and not part of Android - you can also view your daily usage, and change your data budget in the app. Which is pretty useful as well.
We have both videos embedded down below for you to take a look at. Project Fi is in beta, obviously, and is invite only right now. If you're interested, we suggest you head over to their site and request an invite. I'm sure once they get Project Fi going, it'll be available on more devices, but the biggest reason why it's available on the Nexus 6 only is because it has just about every radio you can imagine. And can support CDMA and GSM networks at the same time. So that's why it'll work on both Sprint and T-Mobile, even though they use different technologies.