AT&T Turbo will boost your service for $7 per month

AT&T has a new optional feature for some of its plans. It’s called Turbo, and for $7 per month, it provides “better speed and stability” for a line of service by upgrading your data plan to “performance data.” AT&T pitches it as an add-on to help with demanding applications, like gaming. Okay, but what exactly is “performance data?” It’s kind of unclear. But we can sort of piece it together based on what it isn’t.

If...