While millions of Americans were watching the Super Bowl, TiVo Inc. was watching some of the viewers.

The leading maker of digital video recorders used its technology to analyze the behavior of its subscribers, seeing which football plays or TV ads they chose to pause and when they chose to do instant replays or slow motion.

Britney Spears apparently was the MVP of the big sporting event, according to the TiVo analysis of 10,000 of its 280,000 subscribers.

TiVo viewers did more instant replays of Super Bowl commercials than they did during the game itself, and the Pepsi ads featuring the sex-symbol singer topped the list, said John Ghashghai, TiVo's director of audience research.

Of the football action, the game-winning field goal by the New England Patriots garnered the most replay attention.

TiVo did not release actual numbers of the times viewers used those instant-replay, or slow-motion functions, but overall, TiVo said the special "Trickplay" features were used throughout the broadcast, with an average of 44 times per household.

The analysis — TiVo's largest of a single, live television event — is the kind of information broadcasters, content distributors and advertisers could use to direct tailored messages as more Americans are expected to bring DVRs in their homes.

Already, the NFL has been paying TiVo for so-called "audience measurement" data. It learned, for instance, that a Budweiser commercial received the most pause-and-replays during an earlier wild-card playoff game.

Other advertisers and networks have worked with TiVo in the past for similar data.

"As this analysis shows, the growth in the use of TiVo technology can have a profound impact on how the Super Bowl audiences of the future will watch and interact with the broadcast," said TiVo's chief executive, Mike Ramsay.

Digital video recorders have been slow to take off, but market research firm Forrester Research projects that the number of U.S. households with a digital video recorder will grow from 800,000 now to 42 million by 2006.

The devices work like a VCR, with a hard drive and interactive schedule that allows people to pause live television, skip commercials with a button or automatically select from a schedule which of their favorite programs to record.

At the same time, DVRs can monitor the viewer's habits and record shows on behalf of the viewer based on their apparent preferences.

Privacy advocates have decried such technologies as household intruders, but TiVo officials stress that it does not disclose personally identifiable information to others. When gathering customer marketing research, the company says it does not link viewer data to their name, gender or age — only into one big database that can identify users by ZIP code.