At the moment, there are at least 35,000 publicly available, unauthenticated instances of MongoDB running on the Internet.
MongoDB, one of the leading NoSQL databases, is well known for its fast performance, flexible schema, scalability and great indexing capabilities. At the core of this fast performance lies MongoDB indexes, which support efficient execution of queries by avoiding full-collection scans and hence limiting the number of documents MongoDB searches.
Starting from version 2.4, MongoDB began with an experimental feature supporting Full-Text Search using Text Indexes .