Based on the method used for data storage, a CMS can be classified into 2 categories
CMS is an abbreviation for Content Management System
Till about a decade ago, web space was expensive and most websites either used HTML or were custom coded. Most websites were designed by specialised web designers and programmers who were familiar with HTML coding and programming language like Perl and PHP.
Over the last few years, a variety of Content Management Systems have been developed which make setting up a website a simple task even for a person unfamiliar with the various programming languages. The website owner only has to input various basic data about his website in the form and the website will be available online. The designated users of the CMS can also update it as per their requirement.
The user can select from a number of open source (free) CMS or paid CMS depending on the complexity of the website and his or her budget. Most large online companies have their own custom made CMS, designed to meet their requirements.