I've noticed with IE7 BETA 2, that at least some of the time, IE7 blocks Google adsense and Yahoo Publisher network ads from showing. If you do a search on "IE7 blocks adsense" you will see that I have no shortage of company in the complaint department!
This could, of course, be really problematic as IE7 is going to be in wide use in a matter of months. The bad thing about it is that there is NO USER PROMPT offering the user an opportunity to "Yes, I want to see the ads". Nothing - the ads simply don't show up at all!
However this turns eventually out, there is a very easy fix for this:
Here is a sample that's been fixed this way, with a sample YPN ad on it:
If you have noticed this problem with IE7 BETA 2 and the above page shows an ad when you click the link, then you know that this fix works.
I'd be interested in reading some comments from other developers who have run into this issue.
BTW, if you are tired of typing g-o-o-g-l-e to get to your favorite search engine, why not try one of the other domains they own, all of which point to their main site?
Here's a nice short one: http://ghut.org/