What is quality link building in seo..?

Best resource for Quality link building is http://www.wordstream.com/link-building

quality linking is getting links to your site from high level domains and those ones related to your website

Quality link building implies the process of backlink building from relevant and high authority webpages with good content. Some of the most effective ways to build quality backlinks are:

Guest posting
Article submission
Press release submission
Social bookmarks
Classified ads
Infographics submission

i think it's a backlink on a quality forum