Sonja Kellinger joined MATES as Business Development Manager in September 2018. In this position she is responsible for the development and expansion of the brand and products. She can draw from her many years of professional experience in the agency industry and her expertise in content marketing. At the same time, she is involved in social media and content marketing at universities. Previously, the media manager (B.A.), who also holds a degree in business psychology (M.Sc.), was Director Strategy at Plan.Net Content Marketing as well as Senior Social Media Manager at the agency webguerillas.