i use a system that work in that point of view, http://www.firstclass.com/ ... i started working on this software like 15 years ago, when it started in a university of Ontario... and they work that way for a time... the client cache the entire site as it is browsed, and you can continue navigate it offline, and when you come again on the site, the system posted the answers you may have written, etc...

but with the load of information transmitted and the now more important use of the net, it is completely obsolete to work that way because now, 90% of the population have internet...