5.2 MySQL

MySQL (http://www.mysql.com) is a for-profit company that distributes GPLed MySQL. MySQL is actually dual licensed. This is possible because of the clause in GPL that states that the GPL does not provide protection for contradiction of other licenses.

As a result, it is possible for an organization to purchase a special license from MySQL so that the modified or embedded MySQL database engine is not open sourced. In other words, an OEM (original equipment manufacturer) can pay for a special (not open source) license so they do not have to comply with some of the points in the GPL.

MySQL, as a company, enjoys financial success from commerical licensing of it products. It also makes money from certifying products, service contracts and other means.