Not one month removed from the federal bench in the Northern District of California, former Magistrate Judge Paul Grewal is already a foil in one of his ex-colleague’s opinions.

U.S. District Judge Vince Chhabria used Grewal’s Twitter feed to make a point about Twitter’s potential liability for unwanted tweets delivered via text message—and to issue a personal thank-you to Facebook’s new litigation director for his contributions to the judiciary.