The last time we heard from T-Mobile, they were offering up rollover data via their ongoing ‘Uncarrier’ initiative. It was (and is) a stellar idea, but we wondered if any other carriers would be bold enough to follow suit. AT&T is on board, and has announced their version of shared data for subscribers, which will launch later this month. According to the carrier, 50 million customers will immediately feel the benefits. Sadly, they didn’t meet T-Mobile’s 10GB free ‘banked’ data.