Microsoft has partnered up with a company called Devicescape, which specializes in offloading cellular data traffic by routing it over its array of Wi-Fi networks. The company has 11 million Wi-Fi hotspots worldwide, and all of them have been tested for reliability's sake. In Windows Phone 8, DataSense will take advantage of Devicescape's technology and will allow users to connect to Wi-Fi, if available, instead of using their data plan while out and about. DataSense will be first activated on Verizon WP8 smartphones.
Unfortunately, while DataSense and Devicescape will help those Windows Phone 8 users find free Wi-Fi around them, the login process is still done manually. However, ways to automate this are currently being developed, so signing on to a nearby hotspot will not require user interaction one day. Since the majority of Devicescape's Wi-Fi access points are located in the U.S., the benefit will be felt mostly by Stateside users.
source: Telecoms via Neowin