"Instant On" is a technological term, typically used to describe a powered device's state change from inactive to active.
An electric lamp is instant on. A kerosene lamp is not - you have to trim the wick, remove the hurricane glass, light a match, and ignite the wick. A television is insant on. Your PC is not, although I wish to god it was. I have a little "boot race" every morning in my office between my various machines. Windows 2000 loses consistently.
Computers should be more like TV - I hit the power switch, the screen lights up, then I can just start turning the dial. I turn the dial to E2, POW. I turn the dial to Textpad, POW. Visio, POW. POW POW POW. I want instant gratification. I can find aerial photosurveys of obscure geographical feaures in 30 seconds. Why does my computer take 5 minutes to boot?
It does give me a chance to bullshit a spell in the company galley, however.