There's been a lot of hype recently about Sun and Google coming up with a web based replacement for Office. I've been quietly skeptical about this one for awhile, but this article says everything I wanted to say about it.
The bottom line - the network isn't reliable enough for day to day applications. Heck, that's why I use POP access to gmail - I don't want to have to rely on network connectivity to look at mail. I take planes and trains often enough that being completely cut off from my mail for hours would be a real problem. I don't use web based aggregators for the same reason - I like having offline access (and Comcast makes sure that I have regular, short term offline experiences even while I'm in my office).
The last thing I want is a graphical VT-100 - and I don't need people explaining that reduced functionality and the danger of a complete loss of service is progress, either.