Simplify the following text for a Grade 9 native English-speaking person.
Original: Craig Alexander Newmark ( born 6 December 1952 ) is an Internet entrepreneur best known for being the founder of the San Francisco-based international website Craigslist .
Simplified: Craig Alexander Newmark ( born on December 6 , 1952 in Morristown , New Jersey ) is the founder of Craigslist .