Anchor text is the text (title) that appears within your hyperlink. In a well-built site the text that makes up the actual anchor link is indicative of the subject matter of the page it links to. Anchor text tells the search engines about the content of your web pages -  what the page is about and how others are perceiving it. In essence, the anchor text is about the relevancy of your webpage based on a keyword. Therefore your anchor text should always be completely relevant to the landing page (destination page) and should contain your keyword or keyword phrase.