I love how I can create a screen version and a print version of the same site. It can be very powerful, and all I have to do is create the two types of CSS files and properly reference them. If the user has a monitor they see the site one way -- and if they print it out, its automatically the other, with no setting changes needed on their part.
My question is about the other types of media. Do they ever get automatically turned on? A computer with a projector output (like classroom setups) won't automatically use the projection CSS would it? Somebody would have to turn it on (assuming they would know to look and if their browser would even allow them -- right?).
I guess my concern is more for tv, projection and handheld medias, and not so much for tty, braille or aural. And I just assume that screen and print for the most part work fine.
Do browsers of people with set top internet boxes connected to their tv automatically look for the tv media? Do cell phone web browsers automatically look for handheld CSS?
If you use the Opera browser, then the "projection" rules are used if you display the page in full-screen mode rather than in a normal window.
For handheld devices, the situation is more difficult - different devices use varying combinations of "screen" or "handheld" rules. It is therefore impossible to depend on a particular behaviour from a class of devices.