In this Mediapost article , Alan Schulman, Executive Creative Director of imc2 suggests that YouTube's decision to use overlay advertising instead of pre-roll or mid-roll video was short sighted. YouTube said that the "roll" ads made viewer numbers decline. Schulman says, maybe the ads weren't any good and maybe they're too long. He advocates a :10 video spot and notes the creative options that can be exploited when the "roll" ads are timely, entertaining, and targeted to the viewer.
Personally, I welcome a shorter length but my biggest problem with the "roll" ads is that usually they keep playing the same one over and over again. Many times on high bandwidth sites the content gets stalled and you need to start over, or pause and press play to make it continue. I was watching "Anchorwoman" on the Fox demand site and I saw the same ad for a movie with Dane Cook and Jessica Alba over and over again. I've always believed that advertising doesn't have to be bad to be good. I think there is always going to be a combination of formats just as there is in non-video advertising.
Interestingly, on YouTube itself many of videos actually are advertisements in their own rite.