Buying online adverts by impression is a tricky business. In fact, the IAB has only recently defined what “impression” should mean: they said that 50% of an ad should be visible to the user for at least one second – not exactly a reassuringly high standard for advertisers, but at least it does eliminate the “impressions” that are never seen by users.
Recently the Financial Times has talked about selling inventory by the time that the advert is displayed, rather than impressions. This is an interesting move and by partnering with Chartbeat, a respected analytics company, the FT will reassure advertisers that they will not burn through all their inventory if someone looks at a page on the FT website and then disappears for lunch.
The FT says that they have three trials running on this basis, and that their research already shows that length of exposure to the advert correlates strongly to effectiveness. It will be interesting to see whether this approach becomes a more popular way of selling advertising, and whether the B2B technical media will embrace the change. It’s pretty clear that if publishers do move to selling by time, it will be the sites with in-depth, quality content that benefit, and sites where users spend less time per page will struggle to show their value.
