The U.S. Securities and Exchange Commission in April issued rules allowing public companies to share information on social media. Almost immediately, wheels began turning 2,700 miles away, in the Seattle headquarters of online real estate company Zillow Inc.

Zillow hit upon the idea of taking questions via Twitter during the company’s next earnings call, only 35 days away. Everyone liked the idea, but no U.S. company had ever done such a thing. It wasn’t clear how, exactly, a public company could exchange information on Twitter and still comply with SEC regulations on investor relations.