Despite how awesome that is, most people still close down all their programs and shut down, only to have to start them up again when rebooting.
The idea behind it is simple. Take pretty much everything on the RAM and copy it to C:\hiberfil.sys, which is read again when the system resumes.
Guy B: "15!"
Guy A: "I only got 3!"
Guy C: "Man, you just got HIBERNATED!"
**Guy A walks by**
**Guy B extends hand**
Guy B: "Gimme five!"
**Guy A keeps on walking**
Guy C: "Man...total hibernation, right there."
Guy A: "It's Friday."
Guy B: "No, it's Saturday."
Guy A: "Friday."
Guy B: "Saturday."
Guy A: "Friday!"
**Guy C walks up**
Guy C: "Hey, it's Saturday."
Guy D: "Dude, you just got hi-ber-NATED!"
Guy A: "You up to a game of Marbles?"
Guy B: "Ha ha, you know I'm going to hibernate you, right?"