Since MongoDB is a document-oriented database such as RavenDB, perhaps the following might give you an idea:
The risk-free nature makes it ideal for storing dynamic data, such as CMS and CRM objects, which the end user can usually configure as necessary or semi-structural data (provided by man). Moreover, Raven offers a powerful indexing mechanism that allows you to define Linq as an index. Raven will take this request and execute it in the background, the result of this Linq request is immediately available as a view you can request. We see that Raven is suitable for:
- Internet-related data such as user sessions, shopping cart, etc. - Raven's document-based means that you can receive and store all the data necessary to process the request in one remote call.
- Dynamic objects, such as user-configurable objects, objects with a large number of optional fields, etc. - Free nature that you do not need to struggle with a relational model for its implementation.
- Persisted View Models - instead of re-creating the view model from scratch for each request, you can save it in your final form in Raven. This results in fewer calculations, fewer remote calls, and improved overall performance.
- Large datasets - the basic repository mechanism for Raven is known to exceed 1 terabyte (per single machine), and the non-relational nature of the database makes it trivial to outline the database on multiple machines, something that Raven can do initially.
From: http://ravendb.net/documentation/docs-what-is-raven