All script apps like forums or e-shops store their data inside a database - a collection of cells and tables that contains all of the website information including items, prices, comments, etc. Whenever you open a certain page, the script connects to the database and retrieves the necessary info, then displays it. The mid-level software which connects the script and the database is called a database management system and one of the most widely used ones is MySQL. The latter is frequently used simply because it can run on different platforms (Windows, Linux, UNIX) and with numerous scripting languages (Java, Perl, Python, PHP), not mentioning its fantastic performance even with large databases. Numerous popular platforms such as WordPress or Joomla employ MySQL databases to store their content.