It's using survey results in how people describe (or guess the name) of a color.
http://blog.xkcd.com/2010/05/03/color-survey-results/
More granular, less easy to read, (but pretty) visualization:
http://www.datapointed.net/visualizations/color/men-women-color-names-d3/
TL;DR
"Basically, women were slightly more liberal with the modifiers, but otherwise they generally agreed (and some of the differences may be sampling noise). The results were similar across the survey—men and women tended on average to call colors the same names."
For Fun...
No one knows how to spell 'fuchsia'.
Here are the color names most disproportionately popular among women:
- Dusty Teal
- Blush Pink
- Dusty Lavender
- Butter Yellow
- Dusky Rose
And men...
- Penis
- Gay
- WTF
- Dunno
- Baige