The measurement company said AT&T garnered 263 million "brand impressions" on CBS' TV coverage, along with 13 million "image-based impressions" on related property CBS SportsLine.com. GM followed with 226 million on TV and a higher 30 million online.
Both advertisers' exposures were driven, in part, by exclusive sponsorships of two prominent aspects of the TV broadcasts, particularly during the high-profile Final Four: AT&T on the halftime show and GM on the pre-game show for Pontiac.
Online, AT&T augmented its TV exposure with sponsorship of March Madness on Demand, where tournament games were streamed live. It's likely that many viewers were multitasking and watching games on both TV and the Web simultaneously, giving AT&T a sort of dual, same-time exposure.
Nielsen may have more insight into the effectiveness of this type of initiative in the future, as it attempts to gauge "two-screen" behavior. It hopes to find a way to determine how many people are watching TV and using the Internet at the same time, and how they consume both by melding data from its NetRatings service and TV panel.
GM received a higher number of online impressions than AT&T, but viewer engagement may have been lower as it focused on traditional banner ads on SportsLine, not live gamecasts.
"More and more people are going to the Web for sports content, raising advertisers' confidence in their online sponsorships," says Michael Pond, a media analyst for Nielsen//NetRatings.
After the telecom and auto giants, Coca-Cola had the third-highest TV impressions with 58 million, Nielsen reports.