Multiple instances of an application

[Curiosity]

With some applications, you can have multiple windows. Many graphics viewers will open a new window for each new picture that you open with them. If I want more than one Firefox or Finder window, I use Command-n to open another one. With text editors that can handle more than one documet at a time, I cannot make a new window.

[whitesaint]

You can run multiple instances of the same application, although it's a little unorthodox. I wouldn't recommend doing it for Carbon or big apps such as Office or Adobe's apps. You can just copy the application (Alt/Option + Drag the Application to where you want it, or just hit Apple/Command + D) and that will make an exact copy of the application. You can then have more than one of the same application running at once. This probably works best with Cocoa applications.