At last month's VideoNuze 2012 Online Video Advertising Summit, our closing session was a big picture debate on the future of online video advertising, featuring AOL's Frank Besteiro, NBCU's Peter Naylor, TiVo's Tara Maitra, TubeMogul's Brett Wilson and YouTube's Suzie Reider, which I moderated.

One of the things the group addresses is whether buyers of online video advertising will prefer an impression-based model (akin to traditional TV advertising) or an engagement-based model (akin to search and other forms of online advertising). I believe it's a key question as it goes to the heart of how video advertising will work and the experience viewers will have online. Within this larger question is the omnipresent issue of measurement - when will there be an accepted currency for online video advertising, and what will it be?

As you would expect from such a diverse group, their answers differed widely. While YouTube is staunchly in favor of an engagement model, with its "TrueView" format leading the way, NBCU is equally insistent on a traditional impressions approach and is baking in non-skippable ads to its online programs. Peter notes that this is the approach that appeals to buyers and, in his experience it doesn't lead to higher viewer abandonment. Suzie says YouTube data demonstrates that when viewers choose their ads, effectiveness and recall are much higher.

Among other things, the group also discussed whether VOD and online video are merging, if ads will become more customized to capitalize on online video's interactive potential, and importantly what's the one big thing that will be different a year from now. It's a highly engaging and informative debate (apologies in advance, it's difficult to hear the audience questions in the last 5 minutes).