Overview
In the broadest sense, Content Management Systems (CMS) are simply tools that allow you to manage content workflow from "authoring to editing to publishing" Morville & Rosenfeld, 2007, p. 358. However, such a definition could easily encompass the more sophisticated "prototyping tools" Morville & Rosenfeld, 2007, p. 360 such as Adobe Dreamweaver, which also allow a complete workflow from creation to publish.
It might be more helpful therefore to view CMS's as integrated systems that exist online, alongside the actual website, that provide a "backend" by which an author can edit the website content directly. CMS's are web-based authoring tools (among other things) that allow page creation and editing without additional "desktop" software.
Why use a CMS? The most important benefit of using a CMS instead of desktop software is that it allows multiple authors to edit a site simultaneously. If multiple authors are required to keep a local copy of a site and upload changes, problems with "versioning" will inevitably occur. Another major benefit is that (to varying degrees) CMS's allow sites to separate roles according to levels of ability. An author might only be given permission to edit actual page content, for instance, and not to make changes that might damage the overall layout or design of a site.
Which CMS is right for my site?
The answer to that depends largely on the type of site you want to build, so it is best to think long and hard about that before making a decision. Having said that however, you could conceivably build the exact same site using any of open source "CMS" tools we are about to review. The reason this is so has much to do with the nature of open source software itself. Open Source software allows users of the software access to, and ability to edit, the actual software code itself. What this means in a practical sense is probably best explained by an imaginary scenario:Say you are a programmer who has built a tool that allows a user the ability to create pages and edit content online (a sort of one person wiki). You release the tool as open source and people begin to use it. Soon these users find their homepages a bit 'static', so request a feature to allow simple news postings on the front page, so someone creates a "news" "module" and allows others to use it. So now we have a tool that might be used as a "wiki" or a "blog", and the process goes on.
This is exactly the scenario (and the mess) we find ourselves in today. Authors create sites using open source software (OSS), then inevitably find a need for a new feature, which someone is duly inspired to create. So we end up with Wikis that can contain dynamic news items, blogs that can have multiple authors and profile pages, and so on. The downside of course is the software becomes increasingly complicated and difficult to use, and probably contains many more "bells and whistles" than you personally have need for.
So, while it is tempting (and possibly inevitable) that a site creator might want to opt for a "CMS" with the most features, it helps to set limits of what you want a website to do, and to choose software that is most focused on that type of site. Here we will focus on three completely different types of "content management systems": Wikis, Blogs, and Integrated Solutions.