Google Sends More Warning About "Unnatural Backlinks" | Advanced SEO, Website Silo Architecture and Content Curation | Scoop.it
Matt Cutts (Google's SEO spokes person) quickly followed up with a "there is no need to panic" message. Apparently the message was not as serious as it was presumed to be.

Either way, a lot of webmasters were freaking out and losing sleep over this.