One thing on which those of us in media could always count was the constant gradual increase of prices. Oh sure, unit rates might drop as audiences came and went, but the underlying metric – the cost per thousand views (CPM) of a target audience – would almost always increase except in times of exceptional economic downturn. When pricing the CPM of an in-demand target such as young adults, the increases could be pretty substantial. 
That truism may no longer hold. Witness the start of this piece from the Media Daily News:
In what could be the first material sign that even network prime-time TV is not immune from the physical laws of a rapidly expanding media universe, the average cost of broadcast prime-time inventory has eroded for the first time since the recession. While the rollback is small — the average prime-time cost-per-thousand (CPM) of buying adults 18-49 on the broadcast networks fell 2.4% to $43.06 in 2014 — the fact that it declined at all during a non-recessionary period may signal that even the most premium advertising inventory has hit the wall on Madison Avenue.
It’s all the stuff you read about in economics class coming to pass, I guess. Inventory is no longer a scarce commodity although one could argue that if we’re still approaching every impression as equal we haven’t learned much. Cross-platform content may be triggering cross-platform buying, and the lower CPM’s from those newer platforms might just be a drag on the older ones. The reality is that we’re moving from buying demographics to buying behaviors and so many of the old measures just aren’t applicable. Men 25-54 can’t really be aligned with “people who visited a car dealer website in the last week” even though both can be purchased. That said, the trend lines for all the CPM’s are headed downward which can’t be a good thing from any ad-supported business model.
I guess if you’re a buyer you don’t mind so much. The problem is that over time much of the high quality bait (read that as content) for the audiences you seek may wither away, lacking adequate financial support from the inventory it generates. The audiences will go elsewhere, of course, but maybe not to something that’s ad-friendly (or ad-supported). Penny-wise and pound-foolish?
Consult Keith 