MySQL is an open source, multithreaded, relational database management system created by Michael “Monty” Widenius in 1995. In 2000, MySQL was released under a dual-license model that permitted the public to use it for free under the GNU Public License (GPL); this caused its popularity to soar. The company that owns and develops MySQL is MySQL AB (the AB stands for aktiebolag, or stock company). Currently, MySQL AB estimates that there are more than 4 million installations of MySQL worldwide, and reports an average of 35,000 downloads a day of MySQL installation software from its site and from mirror sites. The success of MySQL as a leading database is due not only to its price—after all, other cost-free and open source databases are available—but also its reliability, performance, and features.