Google glass creates the possibility of an agent or private house seller giving a tour of a home live to viewers around the world. Viewers would be able to ask them the kind of questions you normally need a viewing for, such as, is the house noisy, what does it smell like; could you just check round that corner.
Obviously this same principle can be used to gain prospective tenants for properties available to let. With prospective tenants asking current tenants and or landlords questions about the property and area.
Possibilities are endless… Be interesting to see if it becomes the norm…