If you have a Comcast cable modem and use a lot of bandwidth, you might surpised to find out the “unlimited” service isn’t actually – Comcast has recently begun sending letters to heavy users telling them to cut their use or face termination. The only problem? The limit is secret.

“SAN JOSE, Calif. – By all accounts, George Nussbaum demands a lot from his Internet connection. He streams video and transfers large files from his office. His family downloads movie trailers and his stepson listens to and buys music online.

Nussbaum subscribes to his cable TV provider’s high-speed Internet service, which, he thought, was built for such high-bandwidth activities. Then, in November, he got a letter from the provider, Comcast Corp., ordering him to dial down his usage or face service termination.

Until last summer, the service was advertised as “unlimited.” … “

> From AP: “Comcast targets Internet ‘abusers’ but won’t reveal limits”