“In 2011, officials at the Federal Communications Commission and the Justice Department moved to block AT&T’s proposed $39 billion acquisition of T-Mobile. That kept the struggling, fourth-place carrier alive as an independent firm. And it led John J. Legere, T-Mobile’s flamboyant, foul-mouthed chief executive, to brand his company the “uncarrier,” and inaugurate a string of measures that have turned every accepted practice in the mobile business on its head. T-Mobile’s resurgence, and the effect it has had on the larger market for cellular service, may hold important lessons for regulators who will soon sit in judgment over the latest enormous broadband proposal, Comcast’s deal to gobble up Time Warner Cable.”