Advocacy groups plan to file a complaint against AT&T, alleging violating the U.S. FCC's net neutrality rules.
Powerline networks operate by sending a modulated carrier signal over your regular AC wiring.
The company’s move is no surprise: Half of its smartphone users -- about 17 million customers -- are on so-called unlimited plans and it could find itself in a legal nightmare if other customers win similar cases.
The bottom line: Industry titan AT&T finished last, while two smaller carriers that piggyback on AT&T's network, Consumer Cellular and U.S. Cellular, ranked tops.
Critics worry the tool lets phones double as spying devices, while the software maker says it is intended to help wireless carriers improve the performance of their handsets by communicating metrics.