Not yet but... read this: Is the NoSQL Meeting Announcing the End of the RDBMS Era?
This is about non-RDBMS data-stores used e.g. by LinkedIn, Facebook, SpringSource, Google.
Here are the names of some of these non-RDBMS data-stores: memcached, Tokyo, Redis, Voldemort, MongoDB and Cassandra, Amazon S3, Hadoop Hive, Maglev and Solr.
Read more about here: Nosql if only it was that easy
Most of them are Key/Value or document database.
They leave up ACIDity and data normalization and predefined data schemas in favor of performances, scalability, flexibility and resiliency.
If you need transactions, full time data consistency and do reporting...