The data tracks which ads are subject to the highest level of fast-forwarding. It has long been suspected that film spots are the most "DVR-resistant," because of the stars who appear in them and the often-pulsating action shown. As a result, some networks have suggested they may look to run them while leading off a pod in order to boost their commercial ratings.

The data shows that among the TiVo universe, the "least fast-forwarded campaign" in April prime time was for the film "Forgetting Sarah Marshall." A particular spot for the film that ran during an episode of "The Office" was the highest-rated single spot during the month.

Todd Juenger, the TiVo executive who oversees the ratings, noted that the "Sarah Marshall" spot appeared in a show that did not make the top-10 highest-rated programs--while the No. 1 show, "Grey's Anatomy" (the episode on April 24), had 33 spots--but only two of those made the top 10 for commercials.

"Viewers are exercising control over which ads they choose to watch," Juenger said. "As DVRs continue to proliferate, understanding which advertisements hold audiences in which programming environments--especially during time-shifted viewing--is crucial."

The second-highest-rated commercial (the ratings are for all viewing and not broken down by demos) was for the Will Smith-starring film "Hancock." That spot and the one for "Sarah Marshall" were also the two highest-rated specifically in time-shifted viewing, meaning that they held up well against viewers eager to fast-forward.

In third place overall was an ad for Ford--likely performing well because it ran strategically within popular show "American Idol." Still, it finished fourth in the time-shifted category.

"Idol"--perhaps because it has a high measure of live viewing--served as the platform for six of the top-10 spots, including two in the Mac campaign.

While the "Grey's Anatomy" episode on April 24 accounted for the single highest viewership, five episodes of "Idol" and three of "Desperate Housewives" cracked the top-10 for most-watched in April.