
Joyn will be a part of 4G LTE plans and enabled on smartphones on on the merged network. It will allow customers to share contact information, status updates, content as well as participate in enhanced chats, which allow group message and provides notifications of read messages. Joyn will also allows video calling over Wi-Fi and Cellular, making it a great alternative to FaceTime.
Users will be able to see the online status of their friends who are available to chat similar to what Google Talk offers. It will also enable location sharing and the exchange of content while on a call or during a chat, which is another great alternative to an Apple’s Find my Friends service.
The joyn service will first debut on the Samsung Attain 4G and will eventually be available to all T-Mobile and MetroPCS customers, irrelevant of the device or OS they are using. More RCS compatible devices will be offered through the rest of this year and the years ahead.
source – MetroPCS