“These customers can still use unlimited data and their speeds will be restored with the start of the next billing cycle,” AT&T said in a statement on Friday. “Before you are affected, we will provide multiple notices, including a grace period.”
AT&T said users in the top 5 percent typically stream video and music using their wireless network instead of Wi-Fi.
"You can send or receive thousands of emails, surf thousands of Web pages and watch hours of streaming video every month and not be in the top 5 percent of data users," AT&T said.
Public advocacy group Public Knowledge bashed the announcement on Monday.
"AT&T's announcement that it will throttle the wireless service of so-called 'heaviest users' of its wireless service is simply the latest example of Internet rationing, an anti-consumer, bait-and-switch tactic being used by Internet service providers,” said Harold Feld, legal director for Public Knowledge.