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In Pictures: Facebook’s most important open source...
One of the original big players in the NoSQL game, Cassandra is still a heavyweight when you need Big Data scalability. While Datastax and others offer Cassandra support now, it was originally open sourced by Facebook in 2008. It is now in use by hundreds of large enterprises and organizations. A leader in the big data and NoSQL space, it remains perhaps the biggest contribution from Facebook.
In Pictures: Facebook’s most important open source projects