Can I use a website as screensaver?

I have done that on the Macintosh. You can set your desktop to display a website, the will refresh every five minutes or so. A similar plugin is available for screensavers (although, what is the point of screensavers, with modern LCD displays that will dim or turn off automaticly). Also you can use your sceensavers as a RSS reader.

What plugin is is then?

Let me know how this works for you: AveDesktopSites is a replacement for Active Desktop on Vista.

http://mpj.tomaatnet.nl/vista/

I think you can

If I use a web page as my active desktop, and that site wants to log me out every hour for inactivity, is there a way to automatically trigger activity?