Rachel Molter, a client partner who is part of the company’s Global Business Group, joined Facebook Chicago 6½ years ago, when, she noted, there were just under 50 people working at the office, a fraction of the 500 staff members they currently employ. Initially, she was hired to help facilitate relationships and advertising with consumer packaged goods companies; but soon transitioned to her current role, working with some of the largest advertisers on the platform.