NEW YORK (AdAge.com) -- The number of people online who click display ads has dropped 50% in less than two years, and only 8% of internet users account for 85% of all clicks, according to the most recent "Natural Born Clickers" study from ComScore and media agency Starcom. As the pool of people who click on banner ads rapidly decreases, it begs the question: Is the long-used click-through rate now officially useless?

Clickers only represent 16% of U.S. internet users, according to ComScore data from March. The study initially found that 32% clicked on display advertising in July 2007. If that first study, released last year, crystallized skepticism that click-through rates weren't the be-all end-all success metric for display, this most recent report might just be the last nail in the digital coffin.