Increasingly there is an expectation that websites (whether large or small) will be current, and will contain the latest news and information.
In this climate it can be crippling for a small company to constantly rely on their designer to make minor changes to the site and therefore the most current information on any site may be many months, if not years old.
Many clients will therefore require at least some ability to edit content idependantly of their designer or developer which is where content management systems come in.
Content Management Systems must be user-friendly, and should be intuitive to use.
Inexperienced users may be easily overwhelmed, so showing and hiding content is one way to limit the information displayed on-screen. This can be accomplished through using a tab system such as this example.