Most pages will have both absolute and relative links. The absolute links link one Web site to another. The relative links link individual pages within a site.
Absolute links must use the entire URL of the page that you're linking to. Some people are used to typing in only a part of the URL, e.g., google, and then letting the browser fill in the rest, e.g., http://www.google.com/. But when you write HTML, whether it's in an authoring program or an HTML editor, you must include the entire URL, including protocol and domain. This is an absolute link, including the entire URL:
Batschelet Web site
E-mail links are also absolutes, but the format is slightly different. Here's an e-mail link:
Batschelet e-mail