Responsive web design is the new thing. It is pretty sweet. Want an example? Go to saltsurf.com and resize your browser window. Sweet no?
The whole responsive web design show got its name from Ethan Marcotte in this wonderful article about responsive web design. He kind of coined a name for a practice that was taking off at the time.
But how is this black magic accomplished you ask? The secret sauce is media queries. (Don't really read the media queries link. It is long dry and boring. Just read the List Apart article. Much better. k?)
Media queries basically ask the device "Hey do you have this?". If the device answers yes, it gets one page. If it says no, it gets another. Nice right? This does require the developer to think up rules of how they want the page to display. Some responsive websites just get smaller while some completely change menu options and even eliminate or use different pictures.
Here are some examples:
So if you want to get started making sweet awesome responsive websites, go download a simple boilerplate here -> http://www.getskeleton.com/
And get on it.
On an aside, I really think that a majority of websites will soon have some of the most important elements of responsive web design. The device world is breaking apart and you have no idea what size of screen people are going to be seeing your stuff on. Best to have a prepared response. (Responsive get it? 🙂