its marketing spin on the internet.
what is the cloud?
computers, servers - which you connect to anywhere anytime. via the internet.
oh wait, thats right, thats how the internet works.
as I said marketing spin on what we already use.
its basically a form of networking, with a new catchy name like phreaddie said. you can save all your data to external servers and then just log onto them from any computer to use the data and change it. microsoft work is on "the cloud" now so you don't even need to install it on your pc etc etc