I've seen this issue on a few random installs of IE8 and can't track it down for the life of me. If you open a new window by using the traditional <a href="fu" target="_blank">bar</a> - IE8 does absolutely nothing when its clicked on. I've dug around google for quite some time, to no avail. Has anyone else experienced this and perhaps has a work-around?
Perhaps the pop-up blocker settings have been changed to "High: block all pop-ups". Check in Tools->Internet Options->Privacy->[Pop-up Blocker] Settings.
As far as I can tell, this behavior has stopped occurring with recent releases of IE8. I think it must have been some sort of security setting that got changed with the later releases of IE8. Thanks to those who answered.
This problem occurs with the latest release of IE8 under Windows 7 too. IE8 does open a new blank tab when you click on such a link, but nothing happens after that.
Regarding the comment "MS wants the user in control": What MS wants is irrelevant. The point is that IE is NOT following the official HTML standards, even now, so many years after IE was first released.
The only pages in which target=_blank should be ignored are those with an "XHTML Strict" doctype. All HTML doctypes and transitional doctypes (the majority of the internet) should work according to the doctype specifications - which say _blank should load the content in a new window.