Google's new algorithm update Penguin has hit a lot of adult webmasters. Some of their pages were hit badly, while others saw no effect at all. Last days I was analyzing weblogs of my own sites and found one site that was hit by Penguin. That's from a list of 50 sites on my first server that I looked at. That's not bad at all. Traffic dropped from 1300 to 750 hits a day. It's a very stable site that mostly relies on search engine traffic. It is online since 2003 and I don't spend more than 3 hours a year of work on this site (yes, you read this right. It is a site concept that is easy to maintain).
Google is tweaking it's search algorithm once again. Last year's Panda update lifted quality sites over content farms using duplicate articles and spun text, a seedy method used in mainstream IM. Adult webmasters were hardly affected by it. Today's Penguin update is hitting porn industry hard. It punishes affiliate sites, TGPs and sblogs while tubes rank higher.
Black Hat SEO has become part in many webmasters' SEO strategies. Unlike stated on blogs and boards of self-acclaimed SEO gurus there is no clear-cut borderline between white hat and black hat SEO anymore. Adding a little bit of the other side is not so bad after all according to theories about Markov Chain, an important metric in statistical mathematics. Markov chain more or less translates to a certain amount of links in a chain of connections will be sick or obsolete and search engines accept this rule of nature. Actually, it's suspected to be part of Google's algorithm. A threshold for 'sick' connections is somewhere close to 20% and there is a possibility for a generous margin added on top.
This means, if you are a super clean white hat and your SEO strategy is 98% straight you are most likely going to be falling behind. Your profile might look artificially built according to assumptions of unnatural growth. Don't misunderstand me, I am not saying you should turn to black hat tactics. Most likely they are going to hurt you if done in a spammy way, but they could help building natural linking profiles and control branding.