Google stepped up its program about having artificial (purchased) links pointing at your site. This isn’t a new policy, but an attempt to becoming more vocal and taking action about this type of behavior.
As of 2012 many site owners have reported getting messages from Google regarding link violations. Scanning Google Webmaster Help forums, will provide adequate explanation. Google, when they detect a site using techniques that are outside Google’s Webmaster Guidelines, specifically, possibly artificial or unnatural links pointing to your site intended to manipulate search ranking, requests that site owners make changes to your site to meet Google’s quality guidelines. Examples of unnatural linking could include buying links to improve page rank or participating in link schemes. Google requests that you make changes, and resubmit your site for reconsideration in Google’s search results. This includes unnatural links pointing to your site that you are unable to control or remove. In those instances, Google requests that you provide details in your reconsideration request.
Google increase notification process is primarily due to egregious violations of Google acceptable quality guidelines. The vast majority of the increase in messages is due to Google’s expanding role to inform and police non acceptable behavior and not because of more warnings about links. It is true that actions on link networks have been more visible lately, but that is only partially responsible for the increased messages. Google has been able to track many link networks; the action being taken are not yet clear but MVI would expect to see many sites ranking dropping if they do not respond. In the past, some bad links might have been suspected and Google may have lowered the rating or the weight of such links. This new program of Google reduces the dependency on those links to improve ranking or indexing.
Google’s algorithm’s may make a mistake and unfairly flag a site for problems. In the past Google doesn’t tell you what’s actually wrong, leading you to guess and make mistakes trying to comply. This new direction by Google is an attempt to get in front of this problem by advising customers what is actually wrong.
Google understands that actions on their part lead to websites losing business. This is Google’s notice to many that you must use the acceptable Google standards to get ranked. And if you do not you will be penalized. This is part of the larger direction of preparing for the social network approach to improved ranking and Google +1.