Two years ago, when dilbert.com was redesigned, Adams talked about the Linux/Unix fast page in a blog post: http://dilbertblog.typepad.com/the_dilbert_blog/2008/04/dilb...

He doesn't explicitly say this, but I think the only way he could convince the owners of the site to have a stripped-down page was to say that the normal design was not usable on Linux. Certainly they want to push people to use the other features and spend money; neither of these things are pushed on the fast page.