In this series of articles, we have discussed several ways to allow users to customize their experience with your Web site by formatting your content in XML and using Extensible Stylesheet Language Transformations to provide the final content.
First, we discussed ways in which you can allow users to choose from a selection of style sheets that control the look and feel and/or the overall layout. From there, we progressed to this discussion, in which we detailed one way to create dynamic style sheets based on selections the user has made.
This is just a basic discussion of concepts. You will undoubtedly find more extensive uses for these ideas and more elegant ways to implement them. In any case, you've got one more tool in your toolkit.