Responsive web design is well established as a web-standard now, but here’s something REALLY cool…. responsive icons.
Responsive icons do not mean that the width of the screen determines how big an icon is displayed; actually it means that a different icon is displayed based on the size it is presented in. This means that screen size does not matter but the size of the icons itself does. This is because some icons will be displayed in various sizes – at the same time, on the same screen.
Try out this demo: http://www.responsiveicons.co.uk