PHP/MySQL is a flexible open-source development system.  Over 45% of the web population uses this combination of PHP (Hypertext Preprocessor) and MySQL.

Search engines, financial systems, and other more complex applications are often better suited to custom coding with systems like PHP/MySQL.

You can see a sample of a custom coded search engine site just completed by Digital WorkHorse at cancertrials4prostate.org

Advantages of Open Source:

Choosing an Open Source platform for your web application can lower your overall technology risk and reduce the cost of development and long-term maintenance. Another bonus is that it doesn’t carry the risk of “vendor lock-in” and forced upgrades by software vendors.

Custom applications can be developed with PHP and MySQL, or organized systems using these same toolsets, such as Drupal, Joomla or WordPress, can be used as a starting point.

Budget and application requirements often dictate the appropriate technology solution.