"Service Pack 2 for Windows XP, in addition to providing a host of security enhancements, will block pop-ups in Internet Explorer by default, Microsoft says. The beta version of the Windows XP update released in December last year always included a pop-up blocker, but the feature was turned off by default. Starting with the latest test version of Service Pack 2 (SP2), called Release Candidate 1 (RC1), pop-up blocking will be activated by default, according to an update to the fact sheet for Windows XP SP2 on Microsoft's Web site."
I truly hope that every Web designer out there who thought that a pop-up windows was a "cool" place to put navigation or another key element to the site is now re-thinking the merits of that approach. Pop-ups must die.