Google really wants people writing web content to start using authorship markup. Not only are they looking to use it as a ranking signal, but it also pushes the Google Profile, which is essentially the backbone of the Google+ user experience.
Granted, you don't need to be a Google+ user (at least at this point) to have a Google Profile, and Profiles existed before Google+, but in Google+, the Profile is essentially the equivalent of the Facebook Wall, and authorship markup places them right in search results with nice little clickable graphics.
In a recent article, we looked at a video Google released discussing how to implement authorship markup on your site. They've now released another one offering a few quick steps to get it to work when you don't necessarily control the CMS of the site you're writing content for. This way, even guest authors can add it.
Google calls it, "a way to make it even easier to annotate your pages and show that there is authorship."
Here are the basic steps:
1. Find your Google Profile
2. Add "?rel=author" on the end of your Google Profile URL
3. Wrap that in an a tag - <a href="that url here"
4. Google wants you to use something like "+Matt Cutts" as the anchor text.
5. Insert that on your article, and point your Google Profile back to the site
"If I can't control the attributes, I can still add a link to this special URL," says Cutts, and it's really as simple as that.