Yesterday afternoon, Glenn Gabe posted "Author Stats is Missing" on Google Plus. For most of the month of July it was accessible, but the data quit being updated by Google on the ninth. This comes shortly after it eliminated photos and circle count, reduced video snippets, and made changes to local and in-depth articles from snippets in the search engine results pages (SERPs).
Many marketers believe that Authorship is a precursor to AuthorRank - the future of SEO as we know it. If this is the case, not having access to authorship data will make future optimization efforts much more difficult.
This means that authors with established Authorship through Google Plus can no longer view impressions, clicks and the average rank of their work. What is Google doing with Authorship? It seems they've done a complete 180 on it.
As an author, this reporting was extremely valuable. People could peer at their work as if they were a search engine and make strategic decisions about their writing through this level of insight.
One of two things is likely happening. Either Google is consciously being less transparent with regards to Authorship or it's not as perfect as most think - meaning its rollout of the SERP changes broke the author stats reporting. Not sure which is the case, but stand by for more commentary on this subject. It's likely going to be the source of much buzz for a while.