It would be great if mongodb supported "Database per user"

Use case is where a new user signs up for a web application. The web application creates a new database for that user and all data in that database is private to that user.

There would be no restriction on the number of databases that can be created.

So there would no longer be a need to store all information for all users in one vast database.

This is especially useful where privacy and security is a concern.