The main driver bringing the cookie-blocking issue to the forefront of the online marketing industry's agenda seems to be the Jupiter report that shows nearly 40% of web users clearing cookies at least once a month. Chatter is definitely up on this issue, and a lot of online marketers are having their "Oh, Shit!" moment, once they hear from their colleagues about how sound the Jupiter research is. Lots of people seem to want to know how their affiliate commissions are being affected. They also want to know about how ad server metrics are being affected and how site measurements regarding unique users may be inflated.
Meanwhile, MarketingVox covered a story about a possible cookie substitute based on Flash. While this would make sense as more advertisers move to Flash-based rich media ads, I'm skeptical about whether it would work in the long-term. Wouldn't consumers resort to blocking Flash or removing the specific component that allows for this kind of tracking? It seems that whatever technologists come up with to solve the problem is susceptible to the whims of the folks who develop anti-spyware tools.