Sam Hananel reports for AP:

Supreme Court Chief Justice John Roberts has temporarily blocked a Senate subpoena that seeks information on how the classified advertising website Backpage.com screens ads for possible sex trafficking.

The order Tuesday came hours after Backpage CEO Carl Ferrer asked the high court to intervene, saying the case threatens the First Amendment rights of online publishers.

A federal appeals court ruled Friday that the website must respond to the subpoena within 10 days. Roberts said Backpage does not have to comply with the appeals court order until further action from the Supreme Court. He requested a response from the Senate by Friday.

The order reads in full:

IT IS ORDERED that the August 5, 2016 order of the United States District Court for the District of Columbia, in case No. 16-mc-621, is hereby stayed pending receipt of a response, due by noon Friday, September 9, 2016, and further order of the undersigned or of the Court

The individual Justice assigned to the circuit (the Chief, for DC) is authorized to stay a lower court's order, but they typically refer the application to the full Court for anything more than a brief stay.  I expect that "further order" will come early next week, and it will be from the full Court.