Smart people: Please explain this
 

http://aws.amazon.com/ec2/

Who would use this and why, and wtf is it for?

Just think of a completely scale-able server environment, run whatever you think will grow on it and don't worry about setting up new servers etc. as it happens with a few clicks.
Or the other way around, your business drops for a while, you just decrease your instances that you need.

Makes sense?

//Edit: Another type of scenario: You expect a large spike in traffic to one of your sites, you start some instances of your site within EC2 and add it to your load-balancer, when the spike is over you turn the instances off and stop paying... (on demand computing)

http://hercshome.com/party.jpg


You mean cloud computing in general?

Before personal computers you had to book runtime on University or commercial mainframes and enter your data and wait for your printout.

Say you run an accounting package with millions of transactions a day, then rather than run it on your own computers you just run the online application, click and go!