Complex sentence: Kevin is one of the leading Internet entrepreneurs in the United States having founded several New York-based businesses, including Gilt Groupe, Business Insider, and 10gen/MongoDB, and he helped build DoubleClick from 1996 to 2005, first as president and later as CEO.
Split into simpler sentences: Kevin is one of the leading Internet entrepreneurs in the United States having founded several New York-based businesses, including Gilt Groupe, Business Insider, and 10gen/MongoDB. Kevin helped build DoubleClick from 1996 to 2005, first as president and later as CEO.