Gerry is right: sometimes XKCD is better than it usual brilliance. Today was one of those days.
You have to click through to the main page to get the context. Do a little clicking and dragging.
Then, when you're finding the interface frustrating, go here instead and use this version. Much easier. (via facebook)
Post Scriptum: While I'm mentioning alternate XKCD format, anyone trying to read the strip on an iPhone or iPad (or, I presume (but don't know personally) on other smartphones/tablets), and who is frustrated that they can't get the mouseover text (always worth it, and often the best-part), should bookmark this page where you just click on the image for it.
Post Post Scriptum, Utterly Unrelated to the Post: It looks like blogger finally did as it's been threatening and removed the old, easy-and-pleasant-to-use interface and replaced it with the new, difficult-and-irritating-to-use-interface. (Slower, too!) I feel like The Dude when he stands there and says: "Well, they finally did it. They killed my fucking car."
Ah well. At least they let me switch back after the first forced-trial and get a few more glorious months of usability out of it. Now it's done. Fucking Nazis. (Are we going to split hairs here? Am I wrong?)