PayPal is unleashing its advertising business on the open web.The company’s ad arm—PayPal Ads—will begin selling programmatic ads to marketers, said Mark Grether, SVP and general manager of PayPal Ads. Grether spoke about the expansion at ADWEEK House during the marketing conference Possible.Up until now, PayPal has only sold ads that ran on its own platform. With the move into programmatic, PayPal is now pitching advertisers on targeted ads that appear on other publishers’ websites.Six-month-ol...