The social housing thing especially is a no-brainer in my opinion. Homeless people, poor families and young folk who like being in city centre apartments could all use it. I know that some newly-built offices are specifically designed so that they can be gutted and repurposed if necessary (usually with the idea of turning them into car parks, which is depressing in its own right, but there's no reason they couldn't be homes instead).
Biting the hand that feeds IT
