In the statement of claim, TREB alleges that Mongohouse participates in an "orchestrated strategy to avoid and elude" the board's multiple attempts over the past two years to shut it down.

The board says in a letter to members that it has received reports that some realtors recorded false sales figures due to customers' privacy concerns.

A Supreme Court decision could unlock a treasure trove of real estate information for buyers and sellers, but one site already offers instant home valuations.