Tim Bray posted a brief set of comments on Ray Ozzie's ETech talk:

He’s pumped about RSS as “the DNA to wire the web”; the connective tissue between active websites. He talks about “Composite Applications”; for example, Unix pipes are weaving together a composite app. Claims < is like “copy”, | like “cut”, and > like “paste”. Then the question arises: “Where is the clipboard of the Web?”

The demo was “Live Clipboard” (integrated with Windows clipboard). “Great way to bridge from Web to PC”. Smart, structured, tagged data on the clipboard. You can paste in a feed object, which then remains dynamic.

Granted, it was pretty well pasted-together vaporware. But the idea might have legs.

I have to admit to being a huge skeptic about the mashup idea. Sure, there have been a few interesting demos on the web, and I'm sure that some mashups might even be useful. However - it's still a house of cards, as far as I'm concerned. Why?

• Who's going to create a mission critical application that depends on some foreign (i.e., not under your control) component that is remote? What happens if it goes offline, or if the people controlling it change the API?
• Non-demo applications tend to have non-trivial APIs, which tend to require intense communication to hammer out. I don't see that happening amongst disconnected groups.

For some social applications like wikis and blogs, sure - this will work fine. For other stuff? I'm completely unconvinced.