Actually th short tern cms is not exactly correct, since there also exists content administration software, which not has to be connected with websites at all, like enterprise content management (ecm) for example.

Using it for a website a cms is separating the content of a site from the layout. All textes and pictures are stored in a database like MySQL for example. This allows to change textes and pics or to enter new ones without any knowledge of website technologies like HTML or CSS. Looking at company sites espacially, where often the core competences are situated somewhere else then in webdesign, it is important to enable an easy maintenance of the website.

Since the content is stored separately from the design in a database it is very easy later to make changes to the layout or to realise a complete redesign. A further great advantage is the possibility to administrate user rights.

There are hundrets, if not thousands, of different content management systems. A good overview you can find on the german site contentmanager.de. Basically we can distinguish the groups open source and license software. Of course the capabilities of the various cms are different as well, beginning by a simple blog software, ending by professionell cms for use in big sized companies. Start to Web is working mainly with the free open source cms TYPO3 and Joomla, whereas especially TYPO3 made already the step to a professional cms, which leaves more then one license software behind itself.