I remember BuzzWord back some time ago when it was in early beta. It was shiny and you could write text and make it bold. But, when Adobe acquired Virtual Ubiquity last October, the project gained significant momentum. Behold the Adobe’s Online Office Suite - Acrobat.com. To make a full circle around the web and back, Adobe released Acrobat 9 which is now more than just internet aware with full support for Flash! (Good God.. we all need new hardware now!).
I don't use online office apps and I never will but I do not underestimate the great potential in them. Google, Microsoft, Adobe... All high rollers have a suite of their own and each has a benefit of their own. Google did brilliant job with their own xhtml/css/javascript tools, and now Adobe with their Flash RIA counterpart. But if I would have to choose, I would definitely choose Google, if not for speed, then for their abnormal server network.