I spent a few minutes to implement some server side browser sniffing in order to promote [Firefox](http://www.spreadfirefox.com/?q=affiliates&id=11248&t=75). It works by detecting whether the visitor uses Microsoft Internet Explorer or not. If it finds the user are still using Internet Explorer, then it will display a warning paragraph above the usual content. To see it in action just open this page in Internet Explorer, or set your browser identification to something resembling Internet Explorer.
And by the way, WordPress’ handling of PHP code is broken, or maybe it is strange interaction between Markdown and WordPress. But either way, I can’t make a post of the code here, and I’m too lazy to fix that :).