Google authorship is Googleís way of linking an author with his/her content. It links authorís G+ page with authorís content. So that content is marked permanently with that author by Google search engine. It reduces the possibilities of getting your content copied by others. Because once the content is linked with your G+ profile, then if anyone else uses it, it will be duplicate content. The simple way to link your content with your Google+ page is entering the links of the websites publishing your content under your contributor sites link in your Google+ profile.