Google posted to its Webmaster Central blog today to address seven questions the company is commonly hearing about authorship, or rel="author".
The post discusses what kinds of pages can be used with authorship, use of company mascots as authors, language issues, multiple authors for a single article, preventing Google from showing authorship, the difference between rel=author and rel=publisher, and use of authorship on property listings and product pages.
Google says it only uses authorship when a page contains a single article (or subsequent versions of the article) or piece of content by an author - not a list of articles or an updating feed - or the page consists primarily of content written by the same author. It needs to have a clear byline on the page with the same name as the one used on the author's Google profile.
"Authorship annotation is useful to searchers because it signals that a page conveys a real person’s perspective or analysis on a topic," writes Maile Ohye, developer programs tech lead for Google. "Since property listings and product pages are less perspective/analysis oriented, we discourage using authorship in these cases. However, an article about products that provides helpful commentary, such as, “Camera X vs. Camera Y: Faceoff in the Arizona Desert” could have authorship."
Google only supports one author per article currently, but says it is experimenting with finding "the optimal outcome" when there are multiple authors. Google wants humans for authorship, so don't use it for your mascot.
On rel=author vs. rel=publisher, Ohye says, "rel=publisher helps a business create a shared identity by linking the business’ website (often from the homepage) to the business’ Google+ Page. rel=author helps individuals (authors!) associate their individual articles from a URL or website to their Google+ profile. While rel=author and rel=publisher are both link relationships, they’re actually completely independent of one another."
If you're wondering if you should have URLs for content in different languages pointing to two separate Google profiles in different languages, the answer is no. Use one Google+ profile in your language of preference.
If you don't want authorship to be displayed in Google results, simply prevent your Google profile from being discoverable in search results. If you don't want to do that, you can just remove any profile or contributor links to the site or remove the markup so it's not connected with your profile.