There are two things you might want to know about XKCD:
- Often you can let your mouse loiter over the cartoon to see the rollover-hover-alt-title text; it's a way of delivering the punchline after you've read the base material
- At times, XKCD's references are so arcane that there is room for help and interpretation, which leaves a niche for ExplainXKCD.com.
Randall Munroe is often quite funny, but at times the webcomic focuses on relationships, physics, or infographics that serve to explain complex topics. For instance, this chart presents the characters and plotlines of several popular stories on a time axis. (It helps to know that Primer is a recursive time-travel movie, major geek points for that.)
Last October, Randall Munroe's fiancée was diagnosed with stage III breast cancer and his work has occasionally referred to their experience. Yesterday's XKCD's infographic is a compelling depiction of the process of cancer, brutal in its frank exposition of odds and outcomes.
It's not funny. It is brilliant. You can find it here (it deserves to be seen in its own setting)