Complex sentence: Cohen wrote for "Slate" starting in 1996; he became best known there for "News Quiz", a satiric reader-participation feature which began in February 1998 and ended in November 2000.
Split into simpler sentences: Cohen wrote for "Slate" starting in 1996. At Slate, he became known for "News Quiz", a satiric reader-participation feature which began in February 1998 and ended in November 2000.