No, really. Here are a few articles. There are more:

http://www.fastcompany.com/3021179/secrets-of-running-a-six-...

http://mashable.com/2013/11/04/bought-apartment-rent-airbnb/

http://www.quora.com/Airbnb/Does-it-make-financial-sense-to-...

The $billion$ numbers don't make me think it is anything otherwise. Compare with the 'Youth Hostel' movement of a foregone age and how that broke even as a charity (no tax), with well meaning folk leaving property to them (no debt) and the 'youths' doing their own cleaning with bedding they brought. AirBnb stinks of speculative bubble money and it is only a matter of time before the rentseekers of the buy-to-let market get their fat arses into it.

This post deserves more upvotes. You are right on spot , Sir. I earn moderate income and nothing from Airbnb but if we are really talking about shortening income gap there has to be check at some level. Right now, with AirBnB model , there is no way to guarantee that this actually helps needy than those who own more than one house/apartment homes. There are chances of ( or infact already happening ?) system abuse where people buy houses solely to list it on Airbnb. I would wholeheartedly expect cities to chip in at this point and make adjustment to tax code to heavily tax those , who solely buy to list houses on Airbnb.