As we said before, Google uses the quality of your backlink profile to help determine how well your website ranks in the organic search results. For this reason, they developed one of their algorithms to take on the role of judging your backlinks and they called it “Google Penguin”.
It’s not a good idea to get on the wrong side of Mr Penguin, he can get quite nasty despite his quite friendly appearance. If you want to stay friends, then he will expect you to monitor and manage your backlink profile to your website, highlighting issues to him as you go.