I'm currently in college and taking a ton of computer science and math related courses, and about twice a week I learn something that makes an Xkcd suddenly become absolutely brilliant. --Elan
Likewise, I was learning integrals when I read this strip. Reading the info text was probably the first time I laughed out loud reading something on the internet. -- Sandbylur
For April 1st 2012, Randell deviced dozens of different strips that would show up based on the users location, browser, OS, and home domain. The alt-text was identical for all of them and said:
'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 browser window size.'
No, sometimes it would say "your web browser", and there may have been a few other permutations.