I know that you may not believe it but I have reading lately a lot of reports like this.
Now, the idea of capped service with metered rates, stern warnings, or cancellations above a monthly limit are fully in fashion. For the last few years, companies like Comcast and Verizon's wired broadband division have warned users about excessive downloads, degraded their service, or canceled their accounts, often with little recourse, and sometimes denying it all the while. Enough states' attorneys general and FCC staff and commissioners have been involved that what was implicit has become explicit, but with the related effect that caps have become much lower than what they were in the ad hoc days before these changes.
I have read about same plans at AT&T so probably the happy days of unlimited broadband are gone and your will start to see in your bill a new charge for browsing too much.