With version 8 Internet Explorer shipped with a built-in list of sites to be displayed in a non-standards, Compatibility View mode. This Compatibility View List identified sites that were "most likely to be displayed better in Compatibility View." While the all of the hubbub about whether or not Microsoft's implementation sucked any less than the previously common Doctype Switching technique for switching browsers' rendering modes was interesting reading, just reviewing the Compatibility View list was almost as equally entertaining.
Anyway, IE 9 has continued to implement Compatibility View, and this time the list of non-compatible sites is now web-accessible. happy reading. Oh, if your site is erroneously on the list just email email@example.com to get it removed.