Quality Link: Like the concept of quality content, a quality link can also be difficult to gauge objectively. However, when it comes to search engine results, a quality link will be one that is concerned more authoritative than a "low quality link."

There are several ways that Google and other search engines might look at a link's quality. One method measures the trustworthiness of the source. If the link comes from a page that is often cited, popular, and used frequently, then it will be of a higher quality than a link from an obscure website.

Other factors that contribute to a link's quality include the age of the source (a newer link may not be as established or trustworthy), the related links or websites for a page, in-content links (which are more likely to be editorial or deliberate links to another site), and co-citation. Co-citation is determined by how one's website is linked within a particular community. This is especially useful for sites that want to establish themselves as an authority in a particular area. If you run a website on classic cars, for example, links to your page would become more trustworthy when they are given by other auto websites.

While it's generally useful to have a page's anchor text matches its links, Google will put more weight on a high-quality link without matching anchor text than a link that has matching anchor text but doesn't have quality content.