“Not too long ago AT&T began sending iPhone customers text messages notifying them they were using what the carrier considered too much data,” James Kendrick reports for ZDNet. “These customers were owners of unlimited data plans, normally a plan that would be safe from hitting a cap.”

“AT&T told the customers if they remained in the top 5 percent of data users in their particular area they would throttle speeds for the rest of that billing period,” Kendrick reports. “True to its word, customers started seeing bandwidth drop to the point of being largely unusable.”

Kendrick reports, “Customers with an existing unlimited plan were grandfathered in, and it’s clear AT&T didn’t like that one bit. The throttling is a direct result of the carrier’s trying to force unlimited customers onto a ‘more reasonable’ tiered monthly plan… As if the throttling wasn’t chicken enough, AT&T refuses to tell the customers how much data they are allowed before getting lousy dial-up speeds imposed. According to AT&T they are throttling the top 5 percent of data users in a given area. That definition is meaningless to the customers affected.”

Read more in the full article here.