Very basic - domain authority vs page authority

[thirsty3]

what does that mean and how is that information valuable?  thank you

[RyanKent]

The best definition of Domain Authority can be found here: http://www.seomoz.org/learn-seo/domain-authority

The best definition of Page Authority can be found here: http://www.seomoz.org/learn-seo/page-authority

In brief, PA is a measure of how likely a specific page is to rank well in search results. DA is a measure of how likely a random page from a given site will rank in search results.

If you were to write a new article on the topic of SEO and place it on a brand new site, it would not rank as well as the same article published on SEOmoz. The reason is SEOmoz has a high DA which provides the article with a boost in search ranking.

DA and PA are metrics which can help SEOs understand rankings better. Understanding these metrics also help evaluate the strength of links from a given web page on a site.