There's been the "Whatismyhouseworth.com"'s out there for years but with no advertising budget like SOLD. The one's were seeing now are companies that are adding something to something they already had. Like the Real Estate Book advertising the site in their print magazine or companies like Zillow which have investment backing.
Fidelity recently started offering a lead generator for agent websites using online home valuation as the hook.
The Real Estate Book has never been kind to its advertisers. They took their advertisers listings and sold use of them for Lending Tree's website. I don't know how leads thru this website get distributed. Do they send leads to the local franchise and they give them out to their favorite advertisors? Or do they sell the leads to non-advertisors?
Real Estate Magazines are trying to beef up their online sites as the print ad business is heading for a shakeout.