If the numbers presented here and here are true — and the rates web sites get for online advertising have really dropped 46 percent since the final quarter of 2007 — my optimism for future business models of journalism just took a dive.

The fundamental monkey wrench the Internet threw at newspapers was the loss of their functional monopolies over local advertising. The Internet is the opposite of a monopoly; the number of potential placements for advertising approach infinity. Basic economics tell you that increasing that supply of potential placements should drive down the price any of them can get. That’s why I’m skeptical, in the long term, of any future news business model based primarily on advertising revenue — there’ll always be more content being created to advertise against, and a single news organization will never be able to keep up.

But if these numbers are right, maybe I’m wrong in seeing that as a long-term problem.

Then again, there’s every possibility these numbers are screwy. They separate out rates for news sites (page 17 of this PDF) and claim CPMs shot up from 36 cents in Q1 to 56 cents in Q2 and back down to 36 cents in Q3. (This, while overall online advertising went from 37 to 34 to 27 over the same span.)

That sort of crazy Q2 bump makes me think they’re dealing with too small a universe of data. (And it’s worth noting that these CPMs are for ad-network-sold display advertising only. Sites make significantly more money off the ads they sell outside ad networks.)