Whats Cloud ? Physical Servers Far Away, Same thing Really, Just that its a Term that has being around for a while but its now that its getting Cheaper and Tech is now at a stage where it is allowing people to use a Cloud Service,
You were always able to play games on a Server from your win 98 Computer. but they just change it to the term Could where you could use any Computer and play games on it from a Server,
IE i have a Mac, i could use my mac to play BF 3 on a Server with every thing Maxed out without effecting my MAC computer. as the game is being Ran on the Server on the "CLOUD Network"
In WAN your Office PC's are all LAN networked then you would have a DLC which allows you to connect to the outside World and to other Servers using VPN.
the cost of VPN has dropped as well..