Camera axes: To invert or not to invert?

If you're the kind of person who likes to browse a game's menu and settings before playing (or if you're the kind of person having trouble with camera rotation in games), you probably know that many first person and third person games allow you to invert the x and/or the y axis of the joystick/mouse for camera movement. But why do we have that option, and why should game developers care about that? Let's see...

New Game+

New Game+ is the name (or one of the names) of the game feature that lets the player restart a game while retaining some of the stuff earned in a previously finished game save, like experience, skills, money, weapons...

The Unsung Secret of Great Games - and How Some Games Get It So Wrong

Interesting paper on how the rhythm of the game's mechanics makes it feel good or not.

The Unsung Secret of Great Games - And How Some Games Get It So Wrong