Google is now selling cellular internet service. Kind of. Today, they announced Project Fi, a MVNO service that taps into multiple-cellular networks as well as Wi-Fi. As a Mobile Virtual Network Operator, Google doesn't own the network it's selling service on--Project Fi piggybacks on Sprint and T-Mobile, and the trick is that compatible phones and SIM cards can seamlessly switch between the networks and open Wi-Fi hotspots without a break in connection (with data encrypted), even if you're making a phone call or streaming video. The catch is that this kind of network switching only works with certified hardware, of which Google's own Nexus 6 is the only device to support at launch. Here's Google's promo video for the service, which doesn't go into many details of how it works:
Splitting data connections between multiple networks can theoretically increase coverage, but the real advantage here is pricing. Project Fi starts at $20 a month for unlimited talk, text, and Wi-Fi tethering, and cellular data is priced at $10 a GB. Google has worked out a deal so that you're only charged based on how much cellular data you use--so you'll be refunded for unused data, prorated. For example, if you sign up for 3GB of data for $50 a month ($20+$30), but only use 800MB, you'll be credited $22 at the end of the billing cycle. Project Fi will also come with a companion app for data usage tracking. Learn more about Project Fi at its website, where you can also request an invite to test the service.