Why have backlinks and what are they?
Backlinks are hypertext (i.e. blue line) links that point to a particular page on your web-site from another web-site. These are seen by Google as a vote from the originating site indicating that the location it is pointing to has some value. Whatever text the link has also tells Google what that page may be about. So if you have ten links pointing at your page that say some variation of “dog training” then your page may appear in the search listings for dog training. Other factors apply here so don’t get wrapped up in this explaination, it is cursory.
Google loves to use backlinks as a voting mechanism. The more links that say dog training from various sources the more likely it is to rise in the search results page for that search term. As long as the links are of decent value (not from spammy sites) Google will count them, raising your ranking and therefore increasing your amount of visitors to your site.
