Heralded as a next-generation web design philosophy and practice, responsive design has been adopted by many in the WordPress theme community, and you can see it in action with the Swagger theme created by Jason over at Themeblvd.
To see what “responsive design” means, open up the Swagger theme preview, and resize your browser window. You’ll notice the elements on the page dynamically change shape and position, depending on the size of your screen.
Check it out on an iPhone too – you’ll see the theme detect that it’s being viewed on a smaller smartphone screen and it re-arranges itself, so you don’t have to do a whole lot of pinching and zooming to see the site.
That’s essentially what “responsive design” means: the theme will respond to whatever device you’re on, and whatever orientation you’re viewing it in (landscape or profile, think iPads.)
Look for the responsive design icon on Lampdogs – it indicates that the Theme you’re looking at is fully responsive.