Bob Ippolito gave a presentation at PyCon 2009 titled "Drop ACID and think about data" where he discussed distributed databases and alternatives to relational databases that follow ACID properties. He covered key-value stores like Dynamo and BigTable used by Amazon and Google, document databases like CouchDB and MongoDB, and column-oriented databases. He noted many companies abandoning ACID compliance in favor of databases that sacrifice consistency for availability and partition tolerance based on the CAP theorem.