Fortunately this is an edge case for me, but… there’s a time for everything. And that time was today.
If you build websites using modern, open standards-based techniques, the last thing you want is to have your Internet Explorer-using visitors see your site in the dreaded “compatibility view”. This monstrosity was created by Microsoft with the advent of IE8, to allow sites (mostly corporate intranets) that require the quirks of IE6 to still look like they’re supposed to when viewed in IE8.
The problem is, IE6 sucks, and it makes modern sites look terrible. So if your users accidentally view your site in compatibility view, it’s going to suck too.
The good news is, it’s easy to force IE8 and later to display your site the way you intended. You can disable compatibility view with this simple meta tag:
<meta http-equiv="X-UA-Compatible" content="IE=9; IE=8; IE=7; IE=EDGE" />
(Source: http://stackoverflow.com/a/10365780)