Data auto-detection in browsers

I mentioned the other day about the coolness of Safari's forthcoming RSS/Atom autodetection, and Ben Hammersley noticed that as well. How much further could this go...?

Mozilla (the full browser) had autodetection of links for next and previous pages, as well as for moving up and down in a hierarchy. There was an extra toolbar that showed these links, but I don't think many people used it as it took up extra room. Also, developers couldn't rely on people having Mozilla so they had to include the navigation features on the page anyway. It seems Mozilla has RSS auto-discovery as well. Anyway, it would be very smart if, on loading the front page of a weblog, for example, part of the status bar was to light up with little icons for all the extra data linked to from that page, all connected to standard protocols for launching helper applications when clicked, such as:

feed: RSS/Atom feeds → Newsreader
cal: Public calendars → Calendar subscriptions
foaf: Personal data → Address Book
xmpp: Jabber username → IM
goim: AIM username → IM
mailto: Email address → Mail
gpg: Public GPG key → GPG key import
magnet: Download link for software → P2P

That kind of thing - basically any persistent data that you might want to export or have people subscribe to could go in a 'link rel' tag and would be automatically picked up by the browser. Update: the Link Toolbar extension for Firefox is able to pick up all the 'link' tags from a page and display them in the status bar, which is most of the way there (Thanks Phil).