Inspired by New York Times columnist Frank Bruni finding Courtney Love's lost iPhone in a cab and returning it to her with the help of the magical Internet (and his assistant), further questions of taxi-synergy crept into our heads. What were the chances that Love would exit a cab next occupied by Bruni? "Well, in a town with 8 million people, half a million tourists, 15,000 taxis around, the chances seem slim," Love told Daily Intelligencer. "But I live on a nice street in the Village, so I'd put the chances a little fatter."
"As far as the probability of getting in a cab that Courtney Love just got out of, you'd have to know how often Courtney Love rides taxis," says Jason Liszka, a director of engineering at Foursquare, who also crunched the numbers using an algorithm analogous to the famous birthday problem from probability theory. "Guessing that it's maybe something like two rides per day, and that there are about 456,000 taxi rides per day in the city, the probability that your ride (or Frank Bruni's ride) is the one right after hers on a given day is two in 456,000, or 0.00044%."
He offered a helpful comparison: "It would be equally surprising if Kim Kardashian got into a cab and found Jimmy Fallon's FitBit."