Link Building 101 - Link Building explained - Yoast: "link building 101 tries to explain the basics of link building and to refute some of the myths around it.
How does a link help your site?
A link to your site 'helps' in four ways:
It adds value to the 'receiving page', allowing it to improve its visibility in the search engines.
It adds value to the entire receiving domain, allowing each page on that domain to improve its rank ever so slightly.
The text of the link is an indication to the search engine of the topic of the website and more specifically the receiving page."