I am thinking about learning XML and the accompanying styling language (XSLT?? please give me info on this... Im looking for the CSS equivalent to XML if there is any) but I dont even know what I can use it for.

If I knew XML pretty good right now, what could I do with it? what will I be able to do with it in the soon-to-be future?

Can XML be used on websites and not just RSS feeds currently? What can it be used for exactly?

I have read the XML primers at w3schools, so I know roughly how it is formed and wirtten, but I dont know what it could be used for other then certain applications.