JSON databases are document databases that use text-based documents rather than column or tabular forms, making them more flexible and user-friendly compared to SQL databases. They store semi-structured data using JSON documents and support nesting, object references, and arrays. JSON databases have several advantages such as storage, schema, and indexing flexibility, horizontal and vertical scaling, and the ability to handle large datasets. They are particularly popular in data science and analytics applications due to their flexible schema and support for multiple concurrent queries.