Pretarget is introducing an ad format that comes with a guarantee for advertisers: namely, that their banner ads are within view on a user's screen in the ad exchange environment.

Pretarget cites research indicates that approximately 89% of display ads load above the fold or appear after a user scrolls down, creating an opportunity for a user to see the banner. It is using the comScore-AdXpose display ad validation technology to enable the format, called Opportunity to View measurement.

The product is a twist on a trend that is gaining traction in the online ad space: cost-per-action online ad model, which also delivers advertisers a promise.

In this space, BrightRoll just introduced an audience guarantee to advertisers for ads that they run on the BrightRoll network. Under the program, called TAG, for Total Audience Guarantee, digital video advertisers only have to pay for the impressions that reach their target audiences. The program informs advertisers how many impressions will reach target audiences before the campaign begins. It then rolls out at scale. comScore's AdEffx Campaign Essentials serves as the verification provider.

Last December YouTube launched its TrueView ad format, which lets users skip ads they don't want to see - and only charges advertisers when the viewer has actually watched the ad. The product comes with a countdown button lets users skip the ad after it plays for five seconds - TrueView Video Ads - InStream.

Later, in some cases, advertisers can offer viewers a choice of three pre-roll options to watch. Google says early results suggest view-through rates of 20-70%.