Mongo DB popularized the “document DB” model which is just storing JSON in a database and offering a way to interact with it roughly like you would data in a traditional relational DB.

7ish years ago, they got fed up with the major cloud providers offering their free software as a service and changed their license to one that is more restrictive.

Of course this is sort of the inevitable outcome: a cloud provider builds a competing product and then “open sources” it in a way that will allow them to grab mind share and eventually erode the company that dared to demand compensation for a “free” product.

Microsoft added a middle finger by announcing it just before mongo released quarterly financials too.