With traditional Web sites, presentation elements, such as header graphics, navigation bars, and font types, are included on every Web page. But "content" — the word Web designers use for the text, images, audio, and video on your Web site — is also on every page. Changes to content can inadvertently affect presentation and vice-versa. To use the same image or article on two different pages, you would have to copy, paste, and even rewrite complicated code. This method can take a lot of time and cause inconsistencies and errors in your Web site.
Extend separates presentation information from content. Instead of including formatting information on each page, Extend applies your Web site template to each page. The design template provides the overall look and feel of your Web site, including font styles and header graphics. Because of this feature, you do not have to format each page separately. All you have to supply is the content. And after you've added your content once, you can reuse it on different pages without copying and pasting.