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Don't misuse your customers' personal information.

That's the warning federal regulators are sending to Internet providers such as Comcast and Verizon, in a reminder that they and other broadband companies are now bound by some of the strictest privacy regulations on the books.

The notice stems from the Federal Communications Commission's new net neutrality policy. Drawing from the same law that regulates legacy phone service, net neutrality prohibits the sharing of your subscriber records with third parties unless you give explicit permission to your carrier.

At a time when customer data has become the way many Internet businesses make a living, these rules represent a significant check on Internet providers — many of which also dream of selling content online.

"The Commission has found that absent privacy protections, a broadband provider’s use of personal and proprietary information could be at odds with its customers’ interests," said the FCC in its advisory Wednesday.

Although the FCC hasn't revealed many specifics on how the privacy rule will be enforced on Internet providers, it's encouraging them to come forward with any questions they might have — a move that will be viewed as a sign of good faith, according to the agency.

One question that immediately jumps to mind is this: How will the FCC view a program such as AT&T's GigaPower Internet Preferences? The service offers you a discount on the company's fastest Internet plans so that AT&T can monitor your browsing activity and, in turn, serve you targeted advertising.

If you're signing up for Internet Preferences, you're opting-in to this tracking. Perhaps in doing so, you've given AT&T your permission to share your customer data. But many consumers may unknowingly sign up for Internet Preferences simply because it reflects, as AT&T puts it, the "best pricing." In which case, can you really say permission was granted?

It's enforcement questions like these that will ultimately determine how strong the government's net neutrality rules really are.