This post by Fred Wilson on
this paper, about Comscore research starting to showing how Display Ads actually work, makes fascinating reading. People have always known that Display Ads do increase traffic, but it has been hard to establish good data so Search Ads have tended to be favoured in recent years. The Comscore data is interesting in that it starts to build the story for display Ads:
The diagram shows the raise in attention, and the slow decay over 4 weeks. Also in the report is information about the difference in overall reach.
....in the studies conducted by comScore, approximately 81% of the consumers who saw an ad received only a display ad, while a much lower 8% received only a search ad. When the lift factors are weighted by the reach of the ad, display ads typically emerge as being able to generate a higher total lift in sales.
In other words, you can't build brands with Search, and Display Ads' economics may be far better than anticipated - maybe better than search even. This is quite timely, as there have been quite a
few arguments advanced recently that Display Ads will suffer far more than search in the next few years.