The nightmare of Webmaster is to fall after a lot of work, in one of the penalties designed by Google to protect themselves from various techniques of modern web spam. I thought then to include a list of the various filters that Google does not declare officially, but that are visible to Seo's, and advice on how to work around them or avoid them. I took cue amend my second opinion from a list appeared in one of the discussions on Blog Searchengineland.com and proposal from an old Seo Expert, Joe Whyte.
The results in response to various queries may not be accurate as shown above due to factors such as the total traffic on the data center approached when required or on the number of similar requests.
We are at the end of the list of most popular filters or assumptions used by Google. The latest advice from good friend, is to scrupulously adhere to the advice given.