Here is my written summary about Penguin 2.1
If you built Web 2.0s ? wiki, elgg, jcow, auto approve articles on PR0 domains with spun content to your money site you may have been affected. Each site can take a certain amount of spam links, but once it crosses a certain threshold your rank. This score is based on factors both onpage and off like domain authority, bounce rate, # of pages, quality of content. Now there will always be exceptions to the rule, but for the most part this appears to be the primary issue. I?ve noticed that sites that used all unique, hand-written content on Web 2.0 links were not affected regardless of the Web 2.0s domain PR. However when spun content was used on domains with lots of authority, the link actually helped to increase rankings and increase the sites spam threshold. Any example would be an article directory like ezinearticles that uses ezinesarticles.com/innerpage and NOT a site like blogspot.com that uses subdomains which are still PR0 like subdomain.blogspot.com. At this point I'm not sure if site age is an issue as newer sites might be staying because they have less spammy links compared to the older sites that some people are saying that are tanking. But across industries for keywords like SEO services we're seeing mainstreethost.com and attracta.com move up and these are some of the oldest domains in the industry.
What can you do to fix the problem? Assume you don't have a brand domain. Wait 3 days and see if there are corrections to the update. If no, enable webmaster tools and tell Google to remove your domain from the index. Then move your site's content to a new domain - KEYPOINT - that has NEVER been registered by anyone ever before. Check this in whois. Do not use a dropped domain. Then upload your content there, get the site indexed and start over with your good content on a fresh domain.
