The document implements a MapReduce operation using MongoDB to count the number of posts by each user with status "active" stored in a collection called c1. Four documents were inserted into the c1 collection. A MapReduce operation was run with a mapping function to emit each user_name with a count of 1, and a reducing function to sum the counts. The results of the operation were stored in a collection called "post_total". The find operation then displays the four documents inserted into the original c1 collection.