Components are reusable content objects that can be shared across multiple pages or sections within your site.
For example, maybe you have an announcement that you want to share across your site such as "Closed on Christmas." Without components, you would most likely have to contact a developer, then give the developer a listing of areas you want the notice to appear. However, in this scenario, you most likely would not be able to edit the content of the notice or control whether or not it is on display, etc.
Utilizing components shifts that control back to the content manager. You could create a notice, and choose which page(s) and/or section(s) of the site you would like it to appear, all using a single interface. This means that although the content may span several pages or sections of the site, you can simply edit the component once and it will update all instances throughout the entire site.
Another function of components is to use them as content templates so that non-technical users can recreate a visual style for a specific type of content without having to start from scratch.
In this exercise, we'll create a component to use on the Home page.