Digital advertisers and publishers seek a better method of counting whether an ad has been delivered. Impressions served is the standard metric, and it’s based on whether the web server delivers an ad as part of a page request.
Unfortunately, with today’s highly cluttered web pages that render slowly, this metric doesn’t tell the advertiser much, as I wrote in a story about comScore’s validated Campaign Essentials (vCE), used by USA Today.
ESPN did something smart when it redesigned the site for its X Games: It used a mobile-style swipe navigation that it says creates 100 percent-viewable impressions. Read about it in my ClickZ article about the mobile-forward X Games site.