Ah the most recent dreaded message of Google Webmasters – “Google Webmaster Tools notice of detected unnatural links to … enter your website address here”. When you receive this message you're essentially notified that Google believes you are gaming the SERP results with use of highly optimized backlinks. As a result, Google will slap on a penalty to your website that will take approximately 3 to 5 weeks and will kill your ranking for the keywords they believe you have been building links for.