The MongoDB Sharding Visualizer is a Google Chrome app that provides an intuitive overview of a sharded cluster, offering two different perspectives: the collections view and the shards view. The visualizer allows users to view the distribution of chunks across shards and rewind the state of the cluster at a specific time. To use the visualizer, users must download the source code from 10gen labs, enable Developer Mode in Google Chrome, and load the extension. The visualizer is an alternative to the printShardingStatus() utility function available in the MongoDB shell.