This actually has nothing to do with repetition. It's a case of inventory. There is a 'chicken and the egg' scenario in online advertising where you can't sell

This actually has nothing to do with repetition. It's a case of inventory. There is a 'chicken and the egg' scenario in online advertising where you can't sell ads if you don't have enough 'inventory' (aka ad impressions) and you can't pay for marketing to bring more viewers/content without $$$ from ads. So what happens is Hulu goes out and sells a few advertisers $100,000 in pre-roll ads. The advertiser is used to paying $15 per pre-roll so the Hulu sales people build some crazy equation based off of those two variables (sometimes they'll add in things like 'value adds' which are basically custom stuff that the ad agencies refuse to pay for) and come up with an impression goal. You read that right, the # of impressions per campaign is solely based on the price of the unit and the amount of the ad buy. It's left to the Adops division to see if they can actually FILL that order. Generally, you'll find that companies like Hulu oversell their inventory between 25-50%. They either underdeliver, hope for some big Digg's or other traffic spikes, or cheat by outsourcing the impressions to other networks. You can tell when Hulu or someone else REALLY fucked up when you see the same ad over and over again for a few days.