You can tell Web 2.0 applications by their distinctive look: soft colors, rounded corners, lower-case sanserif names, and an emphasis on sharing. All jesting aside, Suite75 of The Netherlands has launched a Web 2.0 CAD program: floor planner. It's for interactively creating and sharing floorplans.
(I wasn't able to test it out, because Flash needed to be installed in my Opera v9.2 Web browser, which I thought was, but who knows, maybe a newer version is needed, and I get tired of having to repeatedly download newer versions of Flash, particularly when it's just for some company's self-thought clever animation, although in this case, I can't use the software without it, you get what I mean...)
It looks to me like the company has a 3D product in the works, too, judging by the teaser called Woonwijkwijzer (which means "district indicator lives," AltaVista tells me).