These days, Content Management Systems (popularly known as CMS) are often used to build websites. CMS is mainly used for the websites where contents need to change for very often. Each CMS comes with ready to use "Administration" section. This enables anybody (just anybody) to edit, add or remove text contents and images from the website. So, every time you plan to update your website contents, you don't have to pay hefty amounts to some HTML developer.
Among Content Management Systems, the Open Source ones are very popular eg :Wordpress, Joomla, Drupal etc. Nuvodev has successfully customized, implemented and developed many CMS based website and portals.