And the topic in question? The Saturn V Rocket! Aka, the "Up-Goer Five" .
Hilarious! As is much of xkcd

But it gets better! There's an interactive tool that allows you to compose similar text, flagging non-1000 words as you go. Give it a try, for, say, "I would like to fly to the moon".
And if you can come up with something better than "I would like to fly to the thing that goes around this place" .... I'm buying you a beer! Or a glass of wine! Good luck!
MarkC