33 bits of information can amount to fewer than 33 pieces of information. Quoting from the article: "...knowing your hometown gives me 16 bits of entropy about you".

Edit: a relevant anecdote: when I was in high school, a friend went as an exchange student to Costa Rica. As an experiment, I had her send me a blank postcard with nothing on it but "pohl 68320 USA". It arrived in my post office box without a hitch.