PointRoll analyzed the the ad campaigns they delivered and according to the results (as covered in this eMarketer article) while online video gets all the attention these days, consumers spend more time with online promotions and coupons (30.8 seconds versus 16.26 seconds).

Similarly, the interaction rate (interactions/impressions) is higher for many types of rich media than it is with online video. For example, nearly twice as many consumers interacted with text messages as with video. Remember, though, that these metrics do not correspond directly to branding efficacy or ROI consideration such as purchases.

The interesting question here is whether time = engagement. Is the consumer more engaged because it takes her or him more time to fill out a form? The answer, of course, depends on your goals. For example, entertainment advertisers are probably more interested in interaction than on ROI.

The article has many more details and a very interesting breakdown of ad effectiveness per media type.