Among all of the ranking factors Google consider when looking at a link to a page, anchor text is undoubtedly one of the most powerful. If a link is a vote for a page, the anchor text used to link is one of the clearest signal of why you are linking to that page: what is this page actually about?
So powerful, in fact, that they have created numerous penalties for those that have abused anchor text by creating 100s of links to their sites. (*We don't do that here. Lesson learned, a few too