XOOPS is a rich content management system that can be used for many types of websites, depending on the features you need. It is database-driven, with support for both MySQL and PostgreSQL. XOOPS is modular, where new modules that provide additional functionality can be added, removed, activated, or deactivated easily using the web administration system. Registered users have access to change the appearance of some aspects of a XOOPS site, such as the look and feel (using themes). Administrators can send email to subscribed users, change the site language, and update user permissions.
However, there are some limitations of XOOPS, such as:
Data repository is limited to MySQL and PostgreSQL. If you are using anything else, like Oracle or Microsoft SQL Server, then you are out of luck.
There is no support for scalability or replication, other than replication provided by the database.
XOOPS has no support for data import or data conversion. It is also not fully HTML/XHTML-compliant.
There is no version control of documents, or rollback of changes.
There is no WYSIWYG editing for users.
There is no facility to manage a large number of users other than the web interface, and that becomes unsuitable for more than a small user base.
Despite these shortcomings, which may be addressed in future releases of the XOOPS system, there is plenty to like about XOOPS. Just be aware that if any of the above are a must have for you, then XOOPS may not be the right tool for your needs.