Traffic as shallow leads
A brief observation from the IAB performance marketing forum: the interactive advertising industry seems to consist of people from the direct marketing world, who think in terms of leads, and from media agencies, who think in terms of exposure and traffic.
The DM folks are all abuzz about the varying quality of leads, and there are interesting efforts afoot to value leads individually.
The media folks continue to hunt for a single metric to measure traffic by quantity, rather than quality.
As a naive outsider, my forest view says that traffic is just a form of shallow lead, and like all leads the quality is both variable and relative.