A confluence of societal changes, such as stagnant incomes, a resurgence in demand for living in cities, and resistance to building new housing, has resulted in worsening housing affordability in North America. ‘Sharing’ in housing hearkens back to a previous era, the Gilded Age, that saw even more dramatic societal changes. Recently, ‘apps’ such as Airbnb have captured the imagination of the general public because they help ‘make a market’ in heretofore obscure sharing arrangements. Such efforts fall into two categories: using existing living space more intensively, as with Airbnb, and adding living space, such as via Accessory Dwelling Units. In this chapter it is argued that the first category of efforts has limited potential for social equity gains, because their usability is so limited by household type, socioeconomic status and location. Efforts in the second category fall short because they address less urgent problems of design and construction technology rather than the true barriers of land-use regulation. Possibilities probably exist for apps to facilitate sharing in housing, but they will require a pairing of technological innovation with human empathy, and will therefore be unlikely to ‘scale’ at a rapid rate.