The front page of the site describes itself as a "webcomic of romance, sarcasm, math, and language" which basically translates to geek humour! Quite often you will read the comic and laugh even though you don't really get the joke...
This is all part of the charm of it though, most of the time I have to do a little research to understand it. Every Monday, Wednesday and Friday I get to sit down and chuckle about something obscure which helps to remind me of how much there is to learn out there xD
If you are currently learning anything to do with computer science, it is pretty much law that you at least know about xkcd ;P
I'll leave you with a comic that literally had me LOL'ing for days.
