Here are some key features of "XOOPS":

Database-driven:
· XOOPS uses a relational database (currently MySQL) to store data required for running a web-based content management system.

Fully Modularized:
· Modules can be installed/uninstalled/ativated/deactivated with a click using the XOOPS module administration system.

Personalization:
· Registered users can edit their profiles, select site themes, upload custom avatars, and much more!

User Management:
· The ability to search for users by various criteria, send email and private messages to users through a template-based messaging system.

Supported World-wide:
· XOOPS was created and is maintained by a team of several hard-working volunteers working from all over the world. The XOOPS community has more than dozen official support sites around the world for support of non-English speaking users.

Multi-byte Language Support:
· Fully supports multi-byte languages, including Japanese, Simplified and Traditional Chinese, Korean, etc.

Versatile Group Permissions System:
· Powerful and user-friendly permissions system which enables administrators to set permissions by group.

Theme-based skinnable interface:
· XOOPS is driven by a powerful theme system. Both admins and users can change the look of the entire web site with just a click of a mouse. There are also over 60 themes available for download

Requirements:

· WWW server (Apache, IIS, Roxen, etc)
· PHP 4.0.5 and higher
· MySql Database 3.23