The actual nerdy economics joke there is in the second paragraph, which takes the form: Two economists are walking down the street. One of them sees a $20 bill on the ground. As she bends to pick it up, her colleague says “don’t bother, if that was a real $20 bill someone would have picked it up by now.” She replies, “no see this was left here by a consumer tech startup trying to maximize user growth; their Monthly Active Picker-Upper numbers are doubling every two months.” She picks up the $20 bill and the startup raises money at a $2 billion valuation.

via Matt Levine, my favorite journalist of the last decade, by far.