There's bad ads and then there's this bus advertisement from Airbnb. The tone of it seems, well off and condescending and initially we thought it was a hoax. Turns out, not so much. After contacting the shared-rental service about the ad, Airbnb spokesperson Christopher Nulty sent Engadget the following statement: "The intent was to show the hotel tax contribution from our hosts and guests, which is roughly $1 million per month. It was the wrong tone and we apologize to anyone who was offended. These ads are being taken down immediately." The photo was posted to Facebook and quickly spread to Twitter where it's been condemned by librarians and the public at large.