Musa Tariq is joining Nike to be its chief of social media, leaving his job in the same position at Burberry. He joined Burberry in 2009 and was promoted to global director of social media marketing last year. He also has worked with the ad agencies JWT and Saatchi & Saatchi. His start date and exact title are as yet unknown. Separately, Adam Collins, Nike's U.K. brand communications director, is leaving as part of a reorganization of the company's Western Europe division. He will not be replaced.