If you have been editing your pages in frontpage or another editor like that and then transferring the pages via FTP, or writing documents in word and then sending them to (and likely paying) a webmaster to publish for you... having a content management system behind your site will be like getting handed a printing press in 1440.

Content management systems (CMS's) used to be very expensive investments, that only large companies were able to implement.  Interwoven implementations used to be $100K at the beginning of a deployment.

A revolution came about when open source CMS tools started appearing about 7 years ago.  These have evolved into very robust platforms that can run small sites and blogs, or enterprise scale systems.