W3C Technical Architecture Group:

Third-party (AKA cross-site) cookies are harmful to the web, and must be removed from the web platform. 

[…]

We are strongly in favor of innovations to build sustainable business models on the web platform, but an in-depth discussion of the various possibilities are outside of the scope of this document. From an architectural standpoint, web standards should avoid encoding particular business models that are available to authors, publishers, and web content creators.

Them are some strong words from the W3C that leave no doubt about their opinion to remove third-party cookies from the web. We recently noted that Google is sidestepping COPPA regulations. Something tells me the W3C is publishing this in response to Google dropping its own plans to remove third-party cookies from Chrome. Let the battle begin!