Furthermore, this is the new market! I know in SF and Berlin that people, usually upper middle class ex pats or 'transplants' working in tech or finance, actually rent longer term places through AirBnB because it obviates the need for a rental contract, and they don't have to compete for scarce units in the same way: just pay online through AirBnB and the place is theirs. The units stay on the 'market' because the market has deregulated enough to validate this form of renting. Units that were rented through the traditional market are now more commodified and a cut of the profit is funnelled to AirBnB...