To get a handle on the effectiveness of a given ad, IMMI's data can show, for example, when a panel member is exposed to a movie trailer on TV and whether that same consumer later goes to see the movie. Similarly, IMMI data can show if a panelist watching a promo for a TV program will later watch the show, either on TV or online. IMMI thinks it can expand that idea from films and TV shows to consumer products like shampoo or toothpaste. It is testing its technology with a national grocery store chain. "We follow the same person from end to end," says Tom Zito, IMMI's chief executive.