I'm sorting out my bookmarks, filtering out unblogged links, and many revolve around this.
NYT: "Machine-Made Links Change the Way Minds Can Work Together": "The new collaboration is not necessarily the result of expensive, flashy technology. The real consequence is social; when computers interact differently, the humans who use them do, too. ... The idea is not new. Forty years ago, J. C. R. Licklider, a research director of the Pentagon's Advanced Research Projects Agency, predicted that complicated tasks could be shared by computers and humans, with the computers performing much of the rote work, leaving the higher-level problems of analysis and judgment to humans."
Licklider's 1968 paper "The Computer as a Communication Device" (OK, so it's not forty years yet...) is the second half of this PDF. Start at page 25. If you haven't read this before, do it now. I often pick out a paragraph of this when I'm talking about Groove, comparing the "shared spaces" with our regular collaborative tools (email, IM, fax, phone, web):

When people communicate face to face, they externalize their models so they can be sure they are talking about the same thing. Even such a simple externalized model as a flow diagram or an outline-because it can be seen by all the communicators—serves as a focus for discussion. It changes the nature of communication: When communicators have no such common framework, they merely make speeches at each other; but when they have a manipulable model before them, they utter a few words, point, sketch, nod, or object.

Separately:
It's a small world ("A tiny number of random links can turn a huge network into one in which whole groups can be reached through very few steps");
It used to be an even smaller world ("Given that the universe actually consists of nothing at all, explaining its existence becomes rather easier. The separation of the nothing into energy and gravity is a result of the uncertainty principle");
I still don't have time to understand the Xanadu structures...