Interesting article on ClickZ stating that Tacoda is forming a behavioral ad network:

“The new network will compete most closely with contextual ad programs run by Google and Overture, jockeying for position on publishers’ pages and in advertisers’ wallets. Tacoda plans to use pay-per-click pricing and a self-serve auction marketplace — conventions popularized by the search players. The biggest difference will be that while the search companies target ads based on what their technology determines to be the content of the page, Tacoda’s network will target its ads based upon member publishers’ knowledge of the site visitor. That knowledge will come from registration data and from information about the person’s behavior across the network: what type of content the person visits, what he searches for, etc.”

Personally, I’ve always been much more aligned with the idea of context over behavioral alignment. I may be a suburban father of two who loves music, but that doesn’t mean I want to see ads for tickets to Hairspray while I’m searching for a wi-fi router. An ad for a wi-fi router, on the other hand, would be appropriate and effective at that time. My guess is context will beat behavior (particularly reported behavior rather than actual behavior).