Yes, I rented a flat in Rome right near the Trevi fountain, in a beautiful old stone two storey building with a lovely courtyard. There would have been somewhere between 20 and 40 apartments there.

There was a software / techical business of some sort in one corner, but I don't think I saw anyone else.

(Thank you AirBNB)

Did you rent the flat from AirBnB then? I'm not understanding your comment.

Why the down vote? seriously? I am asking for clarification because I am interested if you were speaking about the upside or the downside? Its not at all clear.

I didn't downvote you.

The thanks to AirBNB was as an aside. I think we rented AirBNB but to be honest not sure; might have been one of the many other under the radar holiday house schemes available in Italy and other places.

However the phenomenon under discussion clearly makes something like AirBNB possible -- and good luck to them.

Whether it is an upside or downside overall -- I do not know.

(I have now upvoted both of your comments)

I think Venice is a unique situation. It's due to the difficulty and cost involved in the maintenance of buildings which are partially underwater and can not be accessed by a van or truck.

Fair amount of stubborn older people living their, not much ability for a young Italian to take on the task of buying a residence. I spent time there, in a house that reminded me of Fightclub, mostly with Iraqis. No Italians.