Building Quality backlinks is one of the most important factors in Search Engine Optimization. It is not enough just to have a lot of backlinks, it is the Quality of backlinks along with the Quantity that help you rank better in Search Engines. A backlink could be considered as a Quality Backlink if 1. The Theme of the backlinking website is the same as your website. 2. It links to your website with the keyword (keyphrase) that you are trying to optimize for.