MongoDB is a document-oriented NoSQL database that is designed for building highly scalable and flexible applications. In comparison to traditional relational databases, which store data in tables with pre-defined schema, MongoDB stores data as JSON-like documents with dynamic schemas. This makes it easier to handle unstructured data and provides more flexibility for developers to store and query data.

MongoDB is highly scalable, which means that it can easily handle large amounts of data by simply adding more nodes to a cluster. It also offers a wide range of features such as sharding, load balancing, automatic failover, full-text search, and geospatial indexing.

As a developer learning Node.js, it is important to understand how you can use MongoDB in your application. You can use the official MongoDB driver for Node.js or an Object Document Mapper (ODM) like Mongoose to streamline your development process.

With MongoDB, you can easily store, update, and retrieve data from your Node.js application. You need to first establish a connection between your Node.js application and MongoDB, which can be done using the MongoClient object. Once connected, you can create databases and collections, and then perform CRUD (create, read, update, delete) operations on them using methods provided by the MongoDB driver or ODM.

Overall, MongoDB is an essential tool to have in your Node.js developer toolkit, as it provides a flexible and scalable database solution that can be adapted to suit almost any project.