When your website is supported by a CMS then you dont have to indulge in complex, incomprehensible coding to update content on it on a daily basis. Most blogs, news sites, shopping sites etc that require constant upgradation of content are based on CMS like WordPress, Joomla, etc. Since the behaviour of CMS supported sites remains similar, their look, theme and plug-in functionality are the only things that set them apart and make them unique.