Since a dozen portals of my clients have suffered serious consequences because of this phenomenon, reported here are some news here and there regarding the topic.
If you think you fall into a similar situation, please contact me!
Attorneys for KinderStart.com, a portal dedicated to children's products, and Google reported a substantial damages claim: "Our main page has lost 70% of visits because of a decision by the arbitrary and opaque Google ".
KinderStart argues that California would lower the engine page-rank of the company's website, used by Google as a criterion for calculating the visibility of a web page. Although partial and certainly not very effective in describing the quality of a website, this "index" is advertised by Google in various ways, for example with its Toolbar. According to the lawyers of the U.S. site that produces a wrong suggestion on the actual popularity of the site itself.
Computer Point
Google does not care about anyone when it comes to borderline practices to gain popularity: in Mountain View are very serious about their PageRank, and any activities suspected of resorting to underhanded tricks soon starts to cause a downgrading of the site you are trying to promote: in the jargon we say that the site was hit by a Google Penalty. [...]
There are also many other situations that can lead to downgrading: a Google Bomb, material copied from another site, a page full of links strategic link.htm etc. The experts now prefer to talk about filters, since the techniques used by BigM have become increasingly sophisticated and are able to cover a wide range of possible tricks.
Atuttonet
Interlinking from the same IP. For interlinking mean when webmasters link all their own sites even if they have irrelevant content, link to many sites with the same ip is considered by google something "bad" so this may be one reason for Many such sites have been downgraded.
The Damned Contest. I think that google does not clearly pleased that a site using this marketing strategy to get a ton of backlinks, it can be a striking esepio Gekissimo that contest with the nokia has got really a lot of popularity and backlinks, and perhaps was demoted for this. (As well as links to sell)
Sell Links. Well this is known, everyone is against accandendo text links ads, but the problem riguara all networks of this kind, even Linklift service purchase and sale of links used by many Italians, to work around this problem would be enough that owners of the networks inserissero the nofollow attribute to links bought, but doing this more people would buy a link?
Trains and more. If we read the rules in the google webmaster guidelines capacity that a web page should not contain more than 100 links, unfortunately trains run from major sites, can easily exceed that number.
Soldiweb
