Wikipedia offers a good general definition of CMS:
A content management system (CMS) is a computer software system for organizing and facilitating collaborative creation of documents and other content. A content management system is frequently a web application used for managing websites and web content. (accessed 16 April 2006)
While many proprietary and open source CMS's are available, open source applications can be downloaded for free, modified extensively at the code level by those with the technical savvy, and typically run on open source operating systems. This makes them a good, often lower cost solution, for educators who
- cannot afford the expensive licenses of proprietary solutions.
- believe that educational dollars are too often spent on technology instead of teacher training with technology.
- would like to use grant money or departmental funding to adapt the software for specific contexts that can then be made available for anyone to use.
- would like to merely experiment with alternatives to those systems provided by their institution.