A content management system (CMS) is a software application or set of related programs that are used to create and manage digital content. CMSes are typically used for enterprise content management (ECM) and web content management (WCM).
Image result for What is content management system (CMS) An ECM facilitates collaboration in the workplace by integrating document management, digital asset management and records retention functionalities, and providing end users with role-based access to the organization's digital assets. A WCM facilitates collaborative authoring for websites. ECM software often includes a WCM publishing functionality, but ECM webpages typically remain behind the organization's firewall.  
Both enterprise content management and web content management systems have two components: a content management application (CMA) and a content delivery application (CDA). The CMA is a graphical user interface (GUI) that allows the user to control the creation, modification and removal of content from a website without needing to know anything about HTML.  The CDA component provides the back-end services that support management and delivery of the content once it has been created in the CMA.
Features of CMSes
Features can vary amongst the various CMS offerings, but the core functions are often considered to be indexing, search and retrieval, format management, revision control and publishing.
·         Intuitive indexing, search and retrieval features index all data for easy access through search functions and allow users to search by attributes such as publication dates, keywords or author.
·         Format management facilitates turn scanned paper documents and legacy electronic documents into HTML or PDF documents.
·         Revision features allow content to be updated and edited after initial publication. Revision control also tracks any changes made to files by individuals.
·         Publishing functionality allows individuals to use a template or a set of templates approved by the organization, as well as wizards and other tools to create or modify content.
A CMS may also provide tools for one-to-one marketing. One-to-one marketing is the ability of a website to tailor its content and advertising to a user's specific characteristics using information provided by the user or gathered by the site -- for instance, a particular user's page sequence pattern. For example, if the user visited a search engine and searched for digital camera, the advertising banners would feature businesses that sell digital cameras instead of businesses that sell garden products.
Other popular features of CMSes include:
·         SEO-friendly URLs
·         Integrated and online help, including discussion boards
·         Group-based permission systems
·         Full template support and customizable templates
·         Easy wizard-based install and versioning procedures
·         Admin panel with multiple language support
·         Content hierarchy with unlimited depth and size
·         Minimal server requirements
·         Integrated file managers
·         Integrated audit logs
Choosing a CMS
There is almost no limit to the factors that must be considered before an organization decides to invest in a CMS. There are a few basic functionalities to always look for, such as an easy-to-use editor interface  and intelligent search capabilities. However, for some organizations, the software they use depends on certain requirements.
For example, consider the organization's size and geographic dispersion. The CMS administrator must know how many people will be utilizing the application, whether the CMS will require multilanguage support and what size support team will be needed to maintain operations. It's also important to consider the level of control both administrators and end users will have when using the CMS. The diversity of the electronic data forms used within an organization must also be considered. All types of digital content should be indexed easily.
CMS software vendors
There is a huge number of both free and subscription-based CMS offerings available for personal and enterprise use. The following are just a few examples of CMS platform providers:

·         SharePoint -: A collection of cloud- and web-based technologies that makes it easy to store, share and manage digital information within an organization.
·         Documentum -: Provides tools for storing and retrieving content rapidly and is known for its fine-grained access control.
·         M-Files -: Uses a meta-tag-based approach to be managing electronic documents.
·         Joomla -: A free and open source WCMS built on an MVC framework. Joomla is written in PHP and offers features such as caching, RSS feeds, blogs, search and support for language internationalization.
·         WordPress -: Another free and open source WCMS based on PHP and MySQL. WordPress can be utilized as part of an internet hosting service (WordPress.com), or it can be deployed on a local computer to act as its own web server (WordPress.org). It is immensely popular amongst the blogging community.
·         DNN -:Provides marketers with the content management tools they need to easily access all their digital assets regardless of where they are stored, publish content to any online channel, personalize it to each visitor and measure its effectiveness.
·         Oracle WebCenter -: Oracle's portfolio of user engagement applications built on their own development framework and offered at a per-CPU licensing cost. Three main products make up the suite: Oracle WebCenter Content, Oracle WebCenter Sites and Oracle WebCenter Portal. One of Oracle's major features is that content can be centrally managed in one location and shared across multiple applications.
·         Pulse CMS -: A proprietary software option designed for small websites that enables a web developer to add content to an existing site and manage it easily and quickly. It does not require a database. It uses Apache with PHP 5 and offers user support for paying customers.
·         Terminalfour -: This company's flagship product, Site Manager, is a proprietary software-based CMS that offers extensive multi-platform support. While the on-premises license can be costly, past updates have been reviewed favorably and it supports a broad user community platform for the exchange of ideas and peer-to-peer help.
·         OpenText -: OpenText's ECM Suite and Web Experience Management are aimed at the enterprise and are available both on premises and through the cloud. OpenText specializes in the management of large volumes of content, compliance with regulatory requirements, and mobile and online content management for enterprise use.
·         Backdrop CMS -: A free and open source CMS that is part of the Drupal project and focused on providing affordable CMS for small and medium-sized organizations. On its own, Backdrop offers just the most basic web content management features, but it can be extended with the help of the various modules available.