Why use a responsive web design? Responsive Web Design has became one of the hotest topics in web-client side development.
Show me a site owner that doesn’t want a solution for all types of screens, optimal SEO support all-in-one code solution.
Responsive web design is still not as common as it will be in the next year or so and as it seems, it will turn out to be a web standard.
Here is a good presentation about the issue:
Here are some useful links about this hot topic: