WordPress (WordPress.org) is a content management system (CMS) based on PHP and MySQL that is usually used with the MySQL or MariaDB database servers but can also use the SQLite database engine. Features include a plugin architecture and a template system, referred to inside WordPress as Themes. WordPress is most associated with blogging (its original purpose when first created) but has evolved to support other types of web content including more traditional mailing lists and forums, media galleries, membership sites, learning management systems (LMS) and online stores. WordPress is used by more than 60 million websites, including 33.6% of the top 10 million websites as of April 2019, WordPress is one of the most popular content management system (CMS) solutions in use. WordPress has also been used for other application domains such as pervasive display systems (PDS).
WordPress was released on May 27, 2003, by its founders, Matt Mullenweg and Mike Little, as a fork of b2/cafelog. The software is released under the GPLv2 (or later) license.
To function, WordPress has to be installed on a web server, either part of an Internet hosting service like WordPress.com or a computer running the software package WordPress.org in order to serve as a network host in its own right. A local computer may be used for single-user testing and learning purposes.
“WordPress is a factory that makes webpages” is a core analogy designed to clarify the functions of WordPress: it stores content and enables a user to create and publish webpages, requiring nothing beyond a domain and a hosting service.
WordPress has a web template system using a template processor. Its architecture is a front controller, routing all requests for non-static URIs to a single PHP file which parses the URI and identifies the target page. This allows support for more human-readable permalinks.
WordPress users may install and switch among different themes. Themes allow users to change the look and functionality of a WordPress website without altering the core code or site content. Every WordPress website requires at least one theme to be present and every theme should be designed using WordPress standards with structured PHP, valid HTML (HyperText Markup Language), and Cascading Style Sheets (CSS). Themes may be directly installed using the WordPress “Appearance” administration tool in the dashboard, or theme folders may be copied directly into the themes directory, for example via FTP. The PHP, HTML, and CSS found in themes can be directly modified to alter theme behavior, or a theme can be a “child” theme that inherits settings from another theme and selectively overrides features. WordPress themes are generally classified into two categories: free and premium. Many free themes are listed in the WordPress theme directory (also known as the repository), and premium themes are available for purchase from marketplaces and individual WordPress developers. WordPress users may also create and develop their own custom themes. The free theme Underscores created by the WordPress developers has become a popular basis for new themes.
WordPress’ plugin architecture allows users to extend the features and functionality of a website or blog. As of June 2019, WordPress.org has 55,131 plugins available, each of which offers custom functions and features enabling users to tailor their sites to their specific needs. However, this does not include the premium plugins that are available (approximately 1,500+), which may not be listed in the WordPress.org repository. These customizations range from search engine optimization (SEO), to client portals used to display private information to logged in users, to content management systems, to content displaying features, such as the addition of widgets and navigation bars. Not all available plugins are always abreast with the upgrades and as a result they may not function properly or may not function at all. Most plugins are available through WordPress themselves, either via downloading them and installing the files manually via FTP or through the WordPress dashboard. However, many third parties offer plugins through their own websites, many of which are paid packages.
Web developers who wish to develop plugins need to learn WordPress’ hook system which consists of over 300 hooks divided into two categories: action hooks and filter hooks.
Phone apps for WordPress exist for WebOS, Android, iOS (iPhone, iPod Touch, iPad), Windows Phone, and BlackBerry. These applications, designed by Automattic, have options such as adding new blog posts and pages, commenting, moderating comments, replying to comments in addition to the ability to view the stats.
WordPress also features integrated link management; a search engine–friendly, clean permalink structure; the ability to assign multiple categories to posts; and support for tagging of posts. Automatic filters are also included, providing standardized formatting and styling of text in posts (for example, converting regular quotes to smart quotes). WordPress also supports the Trackback and Pingback standards for displaying links to other sites that have themselves linked to a post or an article. WordPress posts can be edited in HTML, using the visual editor, or using one of a number of plugins that allow for a variety of customized editing features.
Multi-user and multi-blogging
Prior to version 3, WordPress supported one blog per installation, although multiple concurrent copies may be run from different directories if configured to use separate database tables. WordPress Multisites (previously referred to as WordPress Multi-User, WordPress MU, or WPMU) was a fork of WordPress created to allow multiple blogs to exist within one installation but is able to be administered by a centralized maintainer. WordPress MU makes it possible for those with websites to host their own blogging communities, as well as control and moderate all the blogs from a single dashboard. WordPress MS adds eight new data tables for each blog.
As of the release of WordPress 3, WordPress MU has merged with WordPress.
b2/cafelog, more commonly known as b2 or cafelog, was the precursor to WordPress. b2/cafelog was estimated to have been installed on approximately 2,000 blogs as of May 2003. It was written in PHP for use with MySQL by Michel Valdrighi, who is now a contributing developer to WordPress. Although WordPress is the official successor, another project, b2evolution, is also in active development.
WordPress first appeared in 2003 as a joint effort between Matt Mullenweg and Mike Little to create a fork of b2. Christine Selleck Tremoulet, a friend of Mullenweg, suggested the name WordPress.
In 2004 the licensing terms for the competing Movable Type package were changed by Six Apart, resulting in many of its most influential users migrating to WordPress. By October 2009 the Open Source CMS MarketShare Report concluded that WordPress enjoyed the greatest brand strength of any open-source content management system.
As of June 2019, WordPress is used by 60.8% of all the websites whose content management system is known. This is 27.5% of the top 10 million websites.
Awards and recognition
Winner of InfoWorld’s “Best of open source software awards: Collaboration”, awarded in 2008.
Winner of Open Source CMS Awards’s “Overall Best Open Source CMS”, awarded in 2009.
Winner of digitalsynergy’s “Hall of Fame CMS category in the 2010 Open Source”, awarded in 2010.
Winner of InfoWorld’s “Bossie award for Best Open Source Software”, awarded in 2011.
WordPress has a five star privacy rating from the Electronic Frontier Foundation.