MongoDB is the leading NoSQL database in the market today. It is also so popular that it ranks above a number of SQL databases and is very wide spread.
For those who could not attend MongoDB World 2015 in NYC, you can check out all the presentations here.
ADP is an enterprise that is using MongoDB in a big way, proving that this NOSQL store is not just for startherehereups.
NoSQL databases tend to work well with others including other databases. This excellent presentation shows how to use Redis with MongoDB for big data purposes.
Encrypted data stores are very interesting and not often well-represented. The following presentation tells about the encrypted store for MongoDB.
Finally, Mongodb 3.2 has a number of interesting updates listed here.
If you make it through all of these presentations you will have a deep understanding of many topics specific to MongoDB and to NoSQL in general.