Link texts are words and sentences that are used as links. Outbound link texts are the texts within the < a>...< /a> tags when the tag links to a web page on a different domain. It is believed Google.com gives relevance to search terms in outbound link texts.
Example
Keyword: Internet Marketing
Another source for < a href="http://www.not-your-site.com/Internet-Marketing-Services.html">Internet Marketing Services< /a>.