My opinion might be biased because I'm working on drag and drop z-index issues in IE7 today (which are a NIGHTMARE), but given IE's track record of "being different" I think this will be half-baked and full of bugs and inconsistencies.<p>I fully expect to get support calls from people who opted into this privacy control setting and are wondering why things (more likely phrased as "your web site") aren't working right.
Cool feature, but it probably won't get much use. My mental image of the average IE user does not include configuring their browser, much less finding a good blacklist. This will probably be used mostly in corporate set ups, using a blacklist that the IT department maintains itself.<p>I think the largest possible impact of this feature is that other browser vendors may start offering it, possibly with a pre-populated blacklist. On the other hand, I can't really see Chrome blocking Double Click or Google Analytics.
I definitely like the idea of being able to have more control over how websites use my information. Doesn't Firefox 3 have a feature like this already? Or am I thinking of something else?