Robin Good: If you are curious to see which sites have been badly hit by the new Penguin Google filtering algorithm, here is interesting information.
"The official goal was “to take care” over-optimized websites, containing too many unnatural links, automated content (spinning), keyword stuffing etc. Google tries to kill webspam altogether.
The impact on all keywords queries is about 3.1%, which compared to Panda (with around 12%) is much less.
But Google said more short-head/visible keywords should be affected."
Interestingly web sites that were most negatively impacted, included above all three specific categories:
"a) Database-driven websites – they mainly aggregate information and use large database systems to create as many pages as possible. Sites such as songlyrics.com, great-quotes.com, cubestat.com or lotsofjokes.com fall into this pattern.
b) Press portals and feed aggregators such as pressabout.us, newsalloy.com and bloglines.com were also affected, which makes sense from a Google point of view since these are the website types that are very often created by very aggressive (possibly overly aggressive) SEOs and often contain similar content.
c) A couple of heavily template-based websites were also affected – ticketnetwork.com/ticketcity.com, hotelscombined.com and customerservicenumbers.com fit Google’s anti-SEO bill perfectly when it comes automatically (possibly also spun) content.
d) Furthermore, a lot of sites that copy or rehash other peoples’ content (or are used by their users to do that) were demoted – examples include mayor sites such as digg.com, folkd.com and pastebin.com."
Must read. 8/10
Full article and data: http://blog.searchmetrics.com/us/2012/04/25/google-bad-seo-update-a-first-earthquake-on-the-short-head/