Redis extends the lead in the DB-Engines key-value store ranking
by Matthias Gelbmann, 3 February 2014
Tags: Key-value stores, Memcached, Redis, Riak

Despite very fierce competition, Redis remains the most popular key-value store and they keep getting stronger.

New DB-Engines Ranking shows the popularity of database management systems
by Matthias Gelbmann, Paul Andlinger, 3 October 2012
Tags: Cassandra, DB-Engines Ranking, DB2, Memcached, Microsoft Access, Microsoft SQL Server, MongoDB, MySQL, Oracle

Oracle is the most popular DBMS, MongoDB is the most popular NoSQL system.