docs: mongodb broker

docs/brokers.rst

@@ -76,10 +76,12 @@ Although `SQS <https://aws.amazon.com/sqs/>`__ is not the fastest, it is stable,
 
 MongoDB
 -------
-The
+This highly scalable NoSQL database makes for a very fast and reliably persistent at-least-once message broker.
+Usually available on most PaaS providers, as `open-source <https://www.mongodb.org/>`__ or commercial `enterprise <https://www.mongodb.com/lp/download/mongodb-enterprise>`__ edition.
 
 * Delivery receipts
 * Needs Django's `Cache framework <https://docs.djangoproject.com/en/1.8/topics/cache/#setting-up-the-cache>`__ configured for monitoring
+* Can be configured as the Django cache-backend through several open-source cache providers.
 * Requires the `pymongo <https://github.com/mongodb/mongo-python-driver>`__ driver: ``pip install pymongo``
 * See the :ref:`mongo_configuration` configuration section for options.
 
@@ -94,6 +96,7 @@ However for a medium message rate and scheduled tasks, this is the most convenie
 * Delivery receipts
 * Supports bulk dequeue
 * Needs Django's `Cache framework <https://docs.djangoproject.com/en/1.8/topics/cache/#setting-up-the-cache>`__ configured for monitoring
+* Can be `configured <https://docs.djangoproject.com/en/1.8/topics/cache/#database-caching>`__ as its own cache backend.
 * Queue editable in Django Admin
 * See the :ref:`orm_configuration` configuration on how to set it up.