Google has supported the ability to add authorship tagging to your web pages in order to give authors the ability to get more face time in the search results. But often web sites do not implement them fully. So how do 1 out of 5 results have an authorship image?
David Harry dug into it and found that although many blogs and web sites do not properly markup their web pages with authorship and many do not have authorship at all, those sites may still show an authorship image in the search results. How so?
David saw that when there is a Google+ profile completed with links to “contributed to,” “links” and “other profiles,” Google will pick up that linkage and sometimes show the author’s Google+ profile picture in the search results, as they would with the authorship markup.
Google will often show the author’s profile picture even when authorship is not properly implemented on the web site when the Google+ profile page has the links on the about page.
Since only 9% of tech blogs properly implement the meta data, Google knows they can’t rely on webmasters to get it right. So Google is using other means to make the search results “richer” through backwards engineering the authorship tags.
For more on authorship, see our Definitive Guide To Google Authorship Markup.