As a former realtor, the way Zillow, Trulia and other websites earn money is to sell ad space on all listings including FSBO’s. At the time I was a Premier Agent, Coldwell Banker had a contract with Zillow and Trulia that allowed the agents to pay $149./year (special early bird fee) to have that agent appear solo on their listings without other paid Premier Agents appearing. It was great for my listing.
On the flip side, I did receive plenty of leads (80% not qualified) from consumers who contacted me because I paid Zillow to appear as a Premier Agent.
I agree with Scott that realtors do get the shaft, but these days realtors need to accept they can’t control as much of their listings as they want.