I just realized that the Google authorship feature (by which web content could be related to a Google+ profile) had been disabled in summer 2014. The feature was introduced not long before that and the web ecosystem followed with enthusiasm: content management systems like WordPress offered support (at least via plugins), and the SEO media response was positive. Many articles were published on the importance and usage of this feature, such as:

• vervesearch.com/blog/how-to-implement-the-relauthor-tag-a-step-by-step-guide
• googlewebmastercentral.blogspot.de/2013/08/relauthor-frequently-asked-advanced.html
• searchenginewatch.com/sew/how-to/2275870/structured-data-content-rich-snippets-authorship-vs-author-rank
• seoskeptic.com/structured-data-for-author-pages-and-linked-snippets

And then, suddenly, a posting on Google+:

[…] With this in mind, we’ve made the difficult decision to stop showing authorship in search results.

Another posting from John Mueller:

Edit: In the meantime, we’ve decided to remove authorship completely

What is left is the URL http://plus.google.com/authorship which redirects to https://support.google.com/webmasters/answer/6083347, which shows nothing but:

Authorship markup is no longer supported in web search.
To learn about what markup you can use to improve search results, visit rich snippets.

What’s left are many websites containing wasteful markup. Garbage, and it will remain for years, probably. I just deactivated my Google Author Link WordPress plugin. What a waste of time, for so many people. For the interested ones, the removal of this feature is discussed in some depth in this article.