The latest gravy train is rent-to-rent

I was intrigued to read about "the rapidly growing world of "rent-to-rent" also known as "rent-the-rented" and "multi-let". (The Guardian 29 June 2013)

It seems to be a new version of the shared house or flat; but involving an extra layer of landlords who are themselves renting from a landlord. One example given is: "renting a three-bed house ... converting the lounge and dining room into bedrooms, cramming more tenants in and leaving them with just a kitchen to share."

Anyone have experience of this happening and the impact? (P.S. For some reason, the title of the online version of the Guardian article no longer refers to "the latest gravy train" as in the print version.)