CMS or Content Management Systems is to help simply the creation and maintenance of sites. These systems manage online content, generate web pass, and allow users to upload and change content without requiring technical expertise (Basic CMS, Lynda.com). Some of the pros of hosted solutions are that they offer more toolsets than other services, easy to set up and manage as well as no manual installs, many services include site-building tools, reseller options give you the ability to create a revenue stream from client-hosted sites, and some even allow you to brand your own portal. Some of the cons of hosted solutions are some services can cost more than other CMS solutions, cheaper hosted plans ofter come with ad services or usage restrictions, you can become tied to their hosting plan, sometimes switching to another hosting service can be difficult, and hosted solutions tend to have broad feature sets, not focused ones.
Open source CMS is free and can have a full built website in a matter of minutes. Open source have huge development communities, most licenses allow you to modify source code. Some of the down falls of open source are that they can have hidden costs to implement, technical skills are required to manage an open source CMS, larger corporations will need to have an experienced staff member to manage the platforms, costs can be opened ended if not planned for, and poor planning often means that consultants are only engaged after prior failure.
(Choosing a CMS and CMS Basics, Lynda.com)