A coalition of copyright holders and ISPs like Comcast and Verizon have signed up for the "Copyright Alert System," which will provide notices to consumers if their ISP suspects there is illegal downloading going on.

Do you subscribe to HBO or did you illegally download the latest episode of "True Blood" online? If it's the latter, you might find yourself in receipt of a warning from your ISP, thanks to a new agreement between Hollywood studios and service providers.

A coalition of copyright holders and ISPs like Comcast and Verizon have signed up for the "Copyright Alert System," which will provide notices to consumers if their ISP suspects there is illegal downloading going on.

Many ISPs already provide warnings to users if sketchy behavior is detected, but the Copyright Alert System is intended to provide a standardized approach that all ISPs will use. Going forward, users will get a notice if they are suspected of illegal downloading. If they ignore that message, the ISP might resort to pop-ups or redirecting to special Web sites that display the alert. If those too are ignored, the ISP will turn to "mitigation measures," which could include throttling or permanent re-direction to a warning landing page until contact is established.

"These steps will only be taken after multiple alerts and a failure by the subscriber to respond. This system consists of at least five alerts," the alliance said on its Web site. "We anticipate that very few subscribers, after having received multiple alerts, will persist (or allow others to persist) in the content theft."

Participating ISPs include AT&T, Cablevision, Comcast, Time Warner Cable, and Verizon. The effort also has the support of the Recording Industry Association of America and the Motion Picture Association of America, as well as small and independent studios and labels.

"This is a sensible approach to the problem of online-content theft and, importantly, one that respects the privacy and rights of our subscribers," said Randal S. Milch, Verizon's general counsel.

"Consumers have a right to know if their broadband account is being used for illegal online content theft, or if their own online activity infringes on copyright rulesinadvertently or otherwiseso that they can correct that activity," said James Assey, executive vice president of the National Cable & Telecommunications Association (NCTA).

The alliance insisted that account termination is not part of the alert system, but "section 512 of the Digital Millennium Copyright Act requires that the ISPs have in place a termination policy for repeat copyright infringers as a condition of availing themselves of the Act's 'safe harbor' provision," the group said. "This is why subscribers have a right to know if it has been alleged that content theft is taking place on their accounts, and a right to respond."

ISPs will be made aware of the illegal downloading via "a notice from a copyright holder or its representative," the group said. The ISP matches the IP address identified by the copyright holder with a subscriber account, and then forwards a Copyright Alert to the subscriber. The ISPs, however, will "never provide any personally identifiable information to copyright holders" without a subpoena or court order, the group said.

Users can request an independent review before any of the "mitigation measures" are put into place, but that will cost them $35.

The group denied that the effort is similar to the "three strikes" laws being implemented across the pond because the alerts do not create any new laws or formal legal procedures and do not include account termination.

Update: This story was updated at 4pm to clarify how ISPs are notified.