All icons from this site are Scalable Vector Graphics (SVG) based whenever it is practical so that they look crisp in all screen sizes and densities. Nowadays SVG is widely supported and it should be the default choice for icons.
Sorry, no Internet Explorer <=8. It is enough headache to support Internet Explorer 9 already. Just save a dev's life and enjoy HTML5 and CSS3 goodies, upgrade to newer browsers.
All animations on this site are not made with flash. It is again time for HTML5 and CSS3 and away from Adobe Flash's clunkiness.