For years television networks have used the Nielsen ratings to measure audience response and to guide programming decisions. But some networks have begun hiring a new breed of ratings services that use the Internet to measure viewer "buzz" as it rises to the surface. Canada-based Brandimensions says its robots, crawlers, and spiders traverse 20 billion Web links to fan sites, blogs, and chat rooms to determine "buzz" rankings for TV programs. According to the firm's CEO, the service provides a unique measure of "viral energy."

As industry observers point out, Internet-based tracking and the Nielsen system don't always produce the same results. During a recent sweeps period, Nielsen reported that "CSI" was the most-viewed show. Brandimensions, however, said "My Name Is Earl" produced the most Internet buzz. Such divergent results lead some to question whether Internet-based tracking's validity.

Television networks have long sought to quantify viewer interest based on research other than Nielsen estimates, but it is too early know if Internet tracking will become a dependable viewer metric. If online ratings systems prove to be accurate, someday they may become the new standard for measuring and analyzing viewer buzz.