read about this new venture on O'Reilly Radar. I don't know if they are still looking for beta testers but if they are and you're a frequent traveler it might be worth signing up.
I'm intrigued by the approach they take, as in my reading of the description, it goes in the direction of web 3.0 or the intelligent web, by smartly integrating data and not just document links, which makes it more than a mere mashup.
I'll keep an eye out on it. I'm sure there will be more along this line of thought.