Joomla
Joomla! is a free, open source content management system for publishing content on the world wide web and intranets. The system includes features such as page caching to improve performance, RSS feeds, printable versions of pages, news flashes, blogs, polls, website searching, and language internationalization.
Mambo
Mambo (formerly named Mambo Open Source or MOS) is a free software / open source content management system (CMS) for creating and managing websites through a simple web interface. It has attracted many users due to its ease of use. Mambo also includes more advanced features such as page caching to improve performance on busy sites, advanced templating techniques, and a fairly robust API. It can also automate many tasks such as web indexing for static pages. Mambo can provide RSS feeds, printable versions of pages, news flashes, blogs, forums, polls, calendars, website searching, language internationalization, and other possibilities.
Drupal
Drupal is a free and open source modular framework and content management system (CMS) written in the programming language PHP. Drupal, like many modern CMSs, allows the system administrator to create and organize content, customize the presentation, automate administrative tasks, and manage site visitors and contributors. Although there is a sophisticated programming interface, most tasks can be accomplished with little or no programming. Drupal is sometimes described as a "web application framework," as its capabilities extend from content management to enabling a wide range of services and transactions.   

 <<  Back