NAR cannot sponsor or encourage a boycott of Zillow. It would be unlawful for NAR to discourage members from using any product or service provider. Those decisions are made independently by MLSs, brokers, and agents. Likewise, it would be unlawful for local or state Realtor associations to encourage members to withhold listings or business from any third party, such as Zillow, or adopt policies that would preclude members from doing so.