Offline web apps
Right now, people are working on technology to make web apps that are still usable when the user is offline. Google, notably, is working on that problem with things like Google Gears and Chrome OS.
At the same time, other people are working on ubiquitous network access.
Right now, neither one is quite there, but I’m guessing that, in a bit irony, the offline web-app thing is going to be working and useful right about the time that nobody needs it because network access is ubiquitous.
Then again, considering the current situation in the USA with the telcos, municipal wifi, etc., maybe the offline web-app thing will be ready long before ubiquitous network access is an affordable reality.