Using HTML5 and XFN markup like the rel="author" and rel="me" code, respectively, publishers can now definitively identify themselves as the authoritative author of their published work.
Don't let the acronyms and language throw you. While this is a bit more geeky than most people prefer, the concept is simple. Add a quick little snippet inside your anchor tags (which you likely have already) and let the attribution begin. Google's Webmaster Central help has a simplified how-to.
Why is Google Doing This?
By now you realize Google's Panda update took a lot of sites out of the results. Many of those sites scraped content from other sites (or were at least accused of scraping).
Some of those sites (the wrongfully accused) have been pleading their case about original content. Among other changes, this appears to be one of the ways Google is using to identify original content from the copies that are continuing to outrank the site from which they scraped.
Will This Really Help?
Well, Google seems to think it will. In a recent interview, Matt Cutts indicated that authors content publishers should start using the rel="author" attribute over the new schema.org and other and microformats that exist. Granted, you shouldn't imply anything is a golden rule simply because Matt spoke. However, the help docs clearly show two examples of good practice.
If we've learned one thing over the years, it's that Google likes it when you follow their published guidelines.
It has yet to be reported, however, what happens if someone tries to spam you out of your author attribute. What are your thoughts?