Content Management Systems (CMS) give the developer the tools to build your website solution and you as the owner get easily managed content.
The advantages of a Content Management System or Platform are in short.....
You can update the content of your website on your own terms.
Keep your content fresh.
Not be held hostage by a developer to make simple content changes
Your site will be more dynamic by being upto date and hence more valuable to site visitors (someone still has to maintain the content)
No HTML knowledge required
Your CMS will come with a WYSIWYG editor.
Redesigning your website won’t require a complete site overhaul.
Training Videos are available to show novice users how to edit a CMS site.
You can also use a CMS to create event registration forms, collect fees and donations, and store member information etc.
A CMS is a Content Management System . Most of these now are considered Platforms and have become very sophisticated. The original idea behind such systems was to separate “content ” and “design ”. Content meaning the words on the web page or the images in the content (not images in the design ) and design meaning the colour scheme and page layout. Also instead of having every page being hard coded in HTML the CMS pages are built on the fly using templates and database rules to build the pages as required. This allows the easy search of the website built on a CMS Platform for keywords or phrases. This makes a CMS page Search engine friendly. Site content can be displayed in differing formats. CMS sites load faster by using caching accelerators, allow additional design extensions to be added, allow redesign of layout templates (by a developer) to freshen up the sight without loosing site content, allow content scheduling by date to publish or to unpublish and many other features.
Of course as time has passed these have become very sophisticated and can require more horsepower to serve up the content. The downside is a higher cost of the site initially and the hosting cost is higher than static HTML sites. These additional costs are easily offset by the increased ease of use and the user can control the content and has the ability to publish or unpublish any content (text or images) without coding skills and only needs very basic word processing/spreadsheet program skills to edit CMS site content. The CMS will have predefined templates with specific attributes (e.g. Articles, Galleries, Folders, Products, Forms etc) making the creation of new content without any knowledge of HTML, PHP or SQL etc in a WYSIWYG environment.