Not a huge fan of IE, but this post on David Patten's blog nicely illustrates the ease of use of A9's OpenSearch with IE 7.
I'd previously played with OpenSearch as a quick way to integrate biodiversity sources, and put together a couple that have been registered with A9 (search for "taxonomy" and you'll find them). It's essentially adding a few tags to RSS or Atom feeds, coupled with a simple way to describe the search engine.
Perhaps it's time to play with this a little more. It would be a very simple way to open up some data.
(Via A9 Developer Blog.)
Currently playing in iTunes: Wonderwall by Oasis