ASP.NET Ignores IE7 Compatibility Mode Tag in Web.config

 looks at the <system.web> section of Web.config instead of the <system.webServer> section (which is used by IIS7, unless it's running in compatibility mode). To render this meta tag on every page of your site when running IIS6, I believe the best option is to add it to your MasterPage. I ended up adding the following code block to the OnPreRender event of my MasterPage:

Page.Header.Controls.AddAt(0, new HtmlMeta { HttpEquiv = "X-UA-Compatible", Content = "IE=EmulateIE7" });

The reason I used AddAt instead of just plain Add is because the X-UA-Compatible meta tag apparently has to be the first thing in the page header in order for it to be respected.

Hope this helps someone in the same boat!