Google authorship allows Google to associate your content with your profile on Google Plus. Google is bringing the notion of real world authority into online world.
Your avatar in search results
Your content comes up in search results with your picture and name. It helps to develop your personal brand.
Many studies demonstrated that having author's photo in Google search results increases click-through rate. People are attracted to faces and like to see real people behind the links.
Google does not always show avatars. It decides whether to show your avatar by looking at the overall quality of your content. It is not clear how Google evaluates this 'overall quality'.
Does 'author rank' exist?
It is hard to say with certainty if Google ranks individual authors or use it as a ranking factor in search results.
Google may boost content by established authors higher in search results. But it is hard to prove scientifically with tests.
Google may start promoting content by well-established authors first. Than, over the coming years, Google may gradually boost content from other authors.
Do I need to be active on G+?
It is not necessary to be active on G+ or to have have huge G+ following in order to gain authority with Google. But it may help you in personalised search results (results shown to logged-in Google users).
- Write content on high authority sites which are also focused on your topic.
- Build personal network of people who consume and share your content.