During penguin update, 7 of my client site is completely down, rest of clients all ranking up. So far I manage to recover 4 site, balance 3 sites still suffer. Overall, the new updates still benefit me. Success case study to recover SERP and impression. http://www.seomoz.org/blog/recovering-from-the-penguin-update-a-true-story http://www.seomoz.org/blog/how-wpmuorg-recovered-from-the-penguin-update Summary, have balance of anchor text, cut off spam link, and build more natural link. For long run, focus more on content campaign, instate of link campaign.