[notahacker]

I agree with your point about competition, and I also believe that a broker/agent with a sufficiently large list of property can add value to a search process (they ought to be better at identifying properties that fit your requirements than a couple of grainy photos and a list of bullet points, and competition induces them to show you the most suitable properties first).

Isn't the problem with Craigslist simply spam? The property for rent listings on Gumtree (UK equivalent of Craigslist which is very useful for finding flatshares which don't involve intermediaries) are rendered unusable by spam for fake properties put in place by letting agents who will then subsequently offer you something more expensive and less appealing that actually is on the market. Essentially the agents collecting lists of tenants with multiple fake properties crowd out anyone trying to directly list real properties.