Today's XKCD is entitled Umwelt and has the mouseover text Umwelt is the idea that because their senses pick up on different things, different animals in the same ecosystem actually live in very different worlds. Everything about you shapes the world you inhabit--from your ideology to your glasses prescription to your web browser.
I didn't immediately realize what's going on with this one, but this is what it looks like in Opera, which is how I first viewed it:
Somehow when I first viewed it, I didn't notice the width, and only saw the leftmost two frames.
It turns out that a different image is displayed in Chrome:
Someday soon I'll be near an Internet Explorer, and will look then. The address of this XKCD is http://xkcd.com/1037/