Building good content makes the visitors to look into your website. By fetching an authority on your topic, you will catch the attention of more visitors. When one more website in essence "votes" for the feature of your website by placing a link which points back to it, you are acquiring natural linking. Sites having reciprocal links may just drop your link when it no longer matches their linking strategy.

The more you can put up upon helpful articles, white papers and FAQs etc., the improved reason for visitors to link back to your website because of the good content.