It appeared in 07 many of the larger publishers were moving away from performance deals - ie pay per click/action.
From 04-06 these sorts of arrangements were popular amongst agencies and clients - especially in traditional DM/response categories such as finance.
However last year the main publishers seemed to move away from them - focusing more on higher yield CPM placements and looking to monetise their networks in a smarter fashion.
It appears in 08 there is a big emphasis on performance again. News Digital have released a self-optimising performance product, as have Platform Nine. Drive PM are in aggressively in market, as are AdConion, with packages available across networks and rumour has it Fairfax has a product in development as well. On top of this you have the smaller guys - 3Di, DGM, Max, Response Directive etc all pushing cpc/cpa activity.
You have to wonder why the tables have turned so quickly - why publishers who last year were all about talking up the high value of their users and the primative nature of performance have now changed their tune. Could it have anything to do with the overall market for display growing at a rate lower than many anticipated/forecast and performance being looked to as the revenue saviour? Whatever it is, I think the big player performance push will work against them in the medium to long term as it will decrease the worth of their networks. Nothing does a better job of ruining your $80CPM premium area than some irrelavant, untargeted finance clutter.
Interestingly enough - the only network not looking to push performance heavily appears to be ninemsn - who were pioneers in the area.