There's a very interesting discussion going on over at Search Engine Watch about Google's latest toy - Pay Per Action. We're certainly going to be following this very closely here at IWR Towers, not least because of what PPA represents. In short, Google - and other providers of search and web advertising platforms - are going to make it easier for advertisers to slice and dice audiences. In plain English, that means that advertisers will pay publishers for very specific actions taken by readers of a web site. For example, an advertiser could specify that a reader would have to click on the advertising banner on a web page, navigate through the advertiser's site and buy something before the publisher is paid. At present, Google PPA is in Beta testing, so we won't know much more for a while, but the discussion over at SEW is very interesting reading.
PPA isn't a new thing per se, but it is worth considering it in the light of  Wired's interview with Eric Schmidt,  in which the Google CEO talks about his company's near-single source of income and its place as an advertising engine.