Cassandra implementation at NetFlix
Cassandra is one on the top NoSQL database.
Cassandra is used for example by twitter, eBay, Netflix.
This presentation from a Adrian Cockcroft is available on slideshare.
It's very clear, concrete and pragmatic about Netflix move from inhouse Oracle DB to cloud hosted (at amazon) Cassandra DB.
** Migrating Netflix from Datacenter Oracle to Global Cassandra ** from Adrian Cockcroft