AS you probably already know, backlinks are really important for offpage SEO, they relate to the relationship between your site and other sites on the subject your site is about, and help to determine how Google ranks your site, in their results.

its therefore important to know, how many back links you get, and the quality of those back links.  As this allows you to get a better understand of who links to you, it may also be a chance for you to build relationships with the sites that link to you.

Have a look at this useful site.