Expression Engine is Web Publishing Multisite Manager

ExpressionEngine is a CMS (content management system) developed by EllisLab and written using PHP programming language and MySQL database. The “Core Version” of ExpressionEngine is available free, and you can get “Personal” and “Commercial” versions by paying onetime fee.

The core of this system is highly flexible because of the multiple site manager ExpressionEngine on which all the websites in EllisLab network run.
In brief ExpressionEngine alone take cares of our membership, blogs, contact forms, community forums, wiki, knowledge-base, everything. These days it is fondly used for websites and blogs management. Because of its rich features and flexibility ExpressionEngine is becoming popular these days and easily acceptable among developers compared to CMS like Joomla, Drupal.

The full featured Tag module for expression engine provides a "folksonomy engine" that can be well integrated with ExpressionEngine.

Features of ExpressionEngine can be categorized into: Web Publishing, Template Engine, Add-On Modules and Plugins, Communications, Commenting and Trackbacks, Typography, Tracking, Utilities¸ Member Management, Search, Spam Deterrents, Utilities, Data Caching, Security. Multi-site concept, multi-lingual support, custom module development, blacklist feature implementation, search engine friendly URLs, inbuilt powerful search engine, versioning system etc are some of its interesting features.
The ease with which a user can configure this site and the extent to control things make it most popular.
Expression engine web sites benefit your clients because it is an integrated system. Non technical users can edit site from web browsers directly. ExpressionEngine solutions are reliable, repeatable.