Simple Machines Forum (abbreviated as SMF) is a freeware Internet forum application. The software is written in PHP and uses a MySQL database backend, although multi-database support is being developed for version 2.0. SMF is developed by the Simple Machines development team.
SMF was created to replace the forum software YaBB SE, which at the time was gaining a bad reputation because of problems with its Perl-based ancestor software YaBB[citation needed]. At the time, YaBB was attributed to causing resource allocation problems on many systems. YaBB SE was written as a …

WordPress is a blog publishing system written in PHP. All data is stored in a MySQL database. WordPress is the official successor of b2\cafelog, developed by Michel Valdrighi. The name WordPress was suggested by Christine Selleck, a friend of lead developer Matt Mullenweg.
The latest release of WordPress is version 2.6.2, released on 08 September 2008. It is distributed under the GNU General Public License version 2.

ImpressCMS is a free, open source , community-developed content management system for building and maintaining dynamic web sites, written in the PHP programming language and using a MySQL database.
The ImpressCMS Project was formed in late 2007 as a result of a division in the XOOPS community[1]. Many of the developers for ImpressCMS were veteran developers, designers and users with extensive experience with XOOPS and sought to establish a new community built CMS with a philosophy of openness, community contributions and continual improvements in code and features. The core platform …

Drupal is a free software package that allows an individual or a community of users to easily publish, manage and organize a wide variety of content on a website. Tens of thousands of people and organizations are using Drupal to power scores of different web sites, including

Community web portals
Discussion sites
Corporate web sites
Intranet applications
Personal web sites or blogs