Mark Koster co-launched the podcast 'Koster & Van Dijk', where he discusses current events, media trends, and business news with co-hosts. The podcast has gained a following for its engaging discussions and expert insights into the Dutch media landscape.

Mark Koster joined De Telegraaf, one of the largest Dutch daily newspapers, where he continues to report on media and business topics. His work at De Telegraaf has been characterized by incisive analysis and a commitment to uncovering the truth behind complex stories.

Koster published 'De Media Maatschap', a book examining the intricate relationships and power dynamics within the Dutch media landscape. The book was praised for its insightful analysis and comprehensive coverage of the media industry's inner workings.

Mark Koster joined Follow the Money, an investigative journalism platform focused on financial and economic issues. His work there included deep dives into corporate malfeasance and media industry dynamics, further solidifying his reputation as a meticulous and fearless investigative journalist.

Koster joined Nieuwe Revu, a Dutch weekly magazine known for its investigative journalism and in-depth features. At Nieuwe Revu, he continued to build his reputation as a journalist capable of tackling complex stories, particularly in the realms of media and business.

Mark Koster published his first book, 'De Mol', which delves into the life and career of Dutch media tycoon John de Mol. The book was well-received for its thorough research and engaging narrative, establishing Koster as an authoritative voice on media moguls in the Netherlands.

Mark Koster began his career at Quote Magazine, a Dutch publication known for its focus on business and finance. During his tenure, he developed a reputation for his sharp analysis and in-depth reporting on the financial sector, setting the stage for his future endeavors in journalism.