Most desktop computers are a pile of interesting sensors, high speed processors, displays, memory. However the web is generally walled off from accessing all this in a simple way. This is generally because of security concerns and the fact that a webbrowser is an extremely large monolithic piece of software. These days with extensions process protection a webbrowser is essentially a poorly designed operation system.
I’d like to see more ideas like Googles Native Client. Virtualization like this might allow you to run essentially any program in any language while surfing the net.