There are "companies," basically very smart people, who run a business renting high-dollar timeshare weeks. These folks may not even own a timeshare. They have the know-how to create a website and rent timeshares from those of us who advertise on RW and TUG. They see our ads for specific dates and have people who find their website before go-koala.com, RW and TUG. These companies then contact us as owners and say they have a renter for our price. We sign and get a check in the mail. Easy-breezy. But they are making money off of what we own.
Redweek's model also makes money from owners and renters, especially through their scam verify/ protect service. There are listings that fail to rent. $59 each for me (I am a repeat customer), and I have cancelled three recently that I rented through Koala (free to list with money taken out of the proceeds and much safer) and two DVC that I rented through the DVC Rental Store.
I don't even consider these companies to be travel agencies. Travel agencies have a full spectrum of services.
There is money to be made on timeshares, that's for sure. Lots of money.