In layman's terms, there are two types of links: inbound and outbound. Outbound links start from your site and lead to an external site, while inbound links or backlinks, come from an external site to yours. e.g. if cnn.com links to yourdomain.com, the link from cnn.com is a backlink (inbound) for yourdomain.com, however the link is an outbound link from cnn.com's perspective. Backlinks are among the main building blocks to good Search Engine Optimisation (SEO).