Why is everyone praising Google Authorship so much? Sure, there are a few good aspects to the program. The author pictures look really good in SERPs. And successful implementation of authorship increases CTR massively and builds your reputation as an author in the eyes of Google and people. But, it also leaves a fairly easy to notice footprint for those who use Authorship while guest blogging with the aim of building links to their own sites. This is like telling Google, “Hey! The person who wrote that genuinely good post last week on my own blog? I’m also the author of this crappy guest post.” Ask me, how do you know? Because it’s easily predictable.
Via Brian Yanish - MarketingHits.com