Broadcast has their CPP (cost-per-point), newspaper their PCI (per column inch), out-of-home their DEC (Daily Effective Circulation), but will online's CPM (cost-per-thousand) be around forever? Probably not.
Unlike online's traditional media counterparts, the currency for evaluating, negotiating and buying media online is becoming obsolete. I've always thought that online biggest downfall is it's accountability, and now that's changing how we buy it. TV, radio, print and out-of-home are all bought on audience estimates and in most cases the analysis stops there. Sure, there's some post evaluation of the media mix and the campaign's overall effectiveness, but rarely is one medium isolated for performance within an integrated campaign. Except for online.
The impressions purchased online (which by the way are actuals vs. estimates) are just the beginning of buying process. Total clicks, click through percentages, time spent in-banner, video plays, etc.... are all carefully reviewed under a microscope with a fine-toothed comb and used to weight the performance of an online ad. So where is the over-analysis of digital media leading us? From realtime and post performance monitoring to prebuy currency.
More and more we will be purchasing our online inventory based on results rather than piles of impressions. It accidentally started years ago with SEM by engines fronting the impressions and advertisers only paying anytime a user clicked on their ad, and now that model has made it's way to digital display. Cost-per-acquisitions, cost-per-leads, and cost-per-clicks are slowly becoming the norm for purchasing online display. Unlike traditional media where inventory is defined and limited, digital inventory expands daily the placement is becoming irrelevant. All advertisers are interested in are the results and with almost infinite inventory available online, results are becoming the new currency and you're never going to see an advertiser complain about that.