Just what is Responsive Web Design?

We’ve all heard the term bandied about and we nod sagely as if we are in the know. But what does it actually mean and why do the web gurus hammer on about it as being an essential part of today’s web site design?   The term Responsive Web Design (RWD) was coined several years ago by Ethan Marcotte and is mentioned in his 2010 article, "Responsive Web Design” (link). To most of us, responsive