Están complicando demasiado la cosa, están saliendo artículos en blogs y plugins que ya no solo hablan de rel=author sino también de rel=me y otras hierbas, el soporte de Google para webmasters lo pincela en blanco y negro:
Author information in search results - Webmaster Tools Help
Me quedo con esto:
Create a link to your Google+ profile from your webpage, like this:
<a rel="nofollow" href="[profile_url]?rel=author">Google</a>
Replace [profile_url] with the your Google+ profile URL, like this:
<a rel="nofollow" href="https://plus.google.com/109412257237874861202?
rel=author">Google</a>
Your link must contain the ?rel=author parameter. If it's missing, Google won't be able to associate your content with your Google+ profile.
Add a reciprocal link back from your profile to the site(s) you just updated.
Edit the
Contributor To section.
In the dialog that appears, click Add custom link, and then enter the website URL.
If you want, click the drop-down list to specify who can see the link.
Click Save.
To see what author data Google can extract from your page, use the
rich snippets testing tool.