How is ad pricing different online and offline? Fundamentally, it isn’t.

At this point, many internet sellers and buyers are reaching for the keyboard to declare this statement heresy. The web is trackable, they will say. It is bought on a per-impression basis, and it is clickable. All true.

They will also want to say that unlike with offline media, there is no scarcity online – that there are countless unsold impressions that are going to waste and that we now have the technology to at least achieve some value around this inventory. But while that’s a commonly held theory, it isn’t completely accurate.

The only medium in recent history that has had true advertising scarcity is network television, and, with this year’s upfront, one might suggest that even this is no longer true. In every other case there has been either unlimited inventory available (magazines and newspapers) or limits that have rarely, if ever, been reached (radio, cable and spot TV).