… the ad unit isn't going anywhere. At 55 percent of all TV ad units, it still remains the go-to format, according to information-contriver Nielsen. Also: "Nielsen Co. says when viewers watch ads in prime time, the majority of messaging still comes in this tried-and-true package." Which is sort of like saying: "When young people write letters and send them by snail mail, the majority of those notes are still written with Bic pens."