Content management systems were invented to deal with the complexity and tedium of managing large collections of HTML documents by hand. A content management system is an application that manages website content in a form that's convenient for editing and maintenance and publishes the content as HTML. Some content management systems generate HTML programmatically on the fly, whereas others generate static files and publish them. Most content management systems are web applications themselves. Users enter and manage content via HTML forms, and the content management system takes care of storing the content in a database of some kind. Generally content management systems provide some kind of facility for creating templates and then merge the content entered by users with the templates to produce a finished website. When templates are updated, all the pages that use those templates automatically have the changes applied to them.
Content management systems were initially deployed at the largest sites, such as online news sites, online catalogs, and technical sites that published lots of data. These systems were generally custom built and rather complicated. Content management eventually became an industry unto itself, with many companies producing large, expensive systems aimed at publishers, large corporate websites, and other customers who had lots of web content and a few hundred thousand dollars to spend to deploy a system to manage that content.
At the same time, content management systems aimed at individuals also became increasingly popular, except that they weren't called content management tools. Instead, they were called weblogging tools, wikis, photo gallery scripts, and so on.
These days, most websites are built using content management systems of some kind, and some of the largest and busiest websites utilize content management tools that were originally aimed at individuals running small sites. For example, one of the busiest sites on the Web, Wikipedia.org, is an encyclopedia written and edited by volunteers that was built using a content management system called a wiki. Wikis started out as a way to make it easy for individuals to quickly publish content on the Web without any knowledge of HTML. Now you can download and use MediaWiki, the tool behind Wikipedia, free of charge. You'll learn more about it later in this lesson.