"It supports cookies just fine. It just doesn't send your info to every third party site that has a pixel on the page."

Look. Either it does, or it doesn't. Either the cookie that google told the browser about is sent back to google as defined in the RFC, or it is not.

"It just doesn't send your info to every third party site that has a pixel on the page."

What info?? The cookie that was previously set by the 3rd party site?

You seem to be muddily suggesting that cookies will be disabled for any images/js/xhr etc inside a page. That would make a ton of websites unusable in any event.

The whole point is moot anyway, as you can track users pretty accurately without using cookies.

It supports normal first party cookie use, but easily blocks third-party cookies. This prevents people like Google from using their own cookies on third party sites.

So right now when you go to, say, autoblog (supposing it uses Google) Google reads some cookie they gave you to figure out who you are, and stores in a db that you went there. Then when you go to Myspace, they read the cookie again, look it up in the db, and know to serve you an ad for cars.

If MSFTs feature were enabled by default, this would be blocked. They could, of course, workaround it somehow, but could they do so while still making installation of Adsense for autoblog as easy as tossing in some js code? That's the threat.

If you want a more detailed technical explanation than I'm capable of giving you, I'm sure you can Google it :)

Yeah I don't think google will need to work too hard to fix that one :/

Unless MS removes even more standards support from the browser like disabling dom methods from js, you'll always be able to toss in some js.

Also it would mean that statcounters, certain iframe login mechanisms etc would be broken in IE.

It'd be pretty cool if IE does become crippled in this way though, less IE users == less headaches.