I was fiddling around with Amazon.com's Alexa and discovered they provide a very DataLibre-style way of updating one's site information:
To update your contact info, you may place an info.txt file containing your contact info in the root of your site for Alexa to fetch.Right-click this link: info.txt. And save it to your computer. Copy the info.txt file from your computer to the root of your site. Verify that the info.txt file is there with your browser. (Go to http://www.jtauber.com/info.txt.) Once you have verified that the file is there, tell us to fetch it by clicking this link: Go Fetch
Well done Amazon! Now if Bloglines did it with OPML, LinkedIn with FOAF, Freshmeat with DOAP, etc...
UPDATE (2004-12-22): Gary Fleming thinks info.txt is a bad idea. I agree with him. While I still like the DataLibre aspect of what Alexa does, Gary's entry persuaded me that requiring a fixed path "/info.txt" is the wrong way to do it. I should have been able to give Alexa my own URI. DataLibre means owning your own URI space too. Thanks Gary for making me realise that!