Dual Monitor Advantage

Okay, I'm a noob about this "dual monitor" thing, can anyone tell me the main advantage of it?

I'm thinking that, is it possible to use one monitor to watch anime (full screen) while I use the other monitor to surf net, chat, watever, etc.? 

Third party software? What the fuck.

If your using a Radeon or Nvidia video card there is no need for third party apps.

You just use the catalyst control center with radeon to set it up the way you like, or the nview wizard with nvidia.

There is all kinds of options. Remember though in windows under Diplay Properties to have the second monitor enabled, drag it to where you have it positioned on your desk and set up the resolution from there.