Google on August 14, granted a patent entitled "Ranking documents" that describes a few ways "how the search company may detect certain "rank-modifying spamming" techniques and then adjust the ranking of those in a manner, where they might lead to the rankings of pages being improved in those search results."
Those practices, referred to in the patent may involve techniques such as: "Keyword stuffing, Invisible text, Tiny text, Page redirects, Meta tags stuffing, and Link-based manipulation."
The US patent 8,244,722 invented by Ross Koningstein assigned to Google was filed on January 5, 2010 reads, "A system determines a first rank associated with a document and determines a second rank associated with the document, where the second rank is different from the first rank. The system also changes, during a transition period that occurs during a transition from the first rank to the second rank, a transition rank associated with the document based on a rank transition function that varies the transition rank over time without any change in ranking factors associated with the document," Bill Slawski, who discovered the patent reports (via).
Here is the specific clause that addresses those techniques in the patent:
"When a spammer tries to positively influence a document's rank through rank-modifying spamming, the spammer may be perplexed by the rank assigned by a rank transition function consistent with the principles of the invention, such as the ones described above. For example, the initial response to the spammer's changes may cause the document's rank to be negatively influenced rather than positively influenced. Unexpected results are bound to elicit a response from a spammer, particularly if their client is upset with the results. In response to negative results, the spammer may remove the changes and, thereby render the long-term impact on the document's rank zero. Alternatively or additionally, it may take an unknown (possibly variable) amount of time to see positive (or expected) results in response to the spammer's changes. In response to delayed results, the spammer may perform additional changes in an attempt to positively (or more positively) influence the document's rank. In either event, these further spammer-initiated changes may assist in identifying signs of rank-modifying spamming.
Google already in its Webmaster guidelines warns against, those who might engage to try to boost their rankings in the search engine in ways intended to mislead it stating:
"Even if you choose not to implement any of these suggestions, we strongly encourage you to pay very close attention to the "Quality Guidelines," which outline some of the illicit practices that may lead to a site being removed entirely from the Google index or otherwise impacted by an algorithmic or manual spam action. If a site has been affected by a spam action, it may no longer show up in results on Google.com or on any of Google's partner sites."
In other blog post "Why did our PageRank go down from 7 to 3?", Google's Matt Cutts, reminds webmasters that selling links that pass PageRank can lead to a Google penalty.
Cutts wrote, "the usual reason why a site's PageRank drops by 30-50% like this is because the site violates our quality guidelines by selling links that pass PageRank. Here's our documentation on that: http://support.google.com/webmasters/bin/answer.py?hl=en&answer=66356 and here's a video I made about this common case: http://www.youtube.com/watch?v=kFcJ7PaLoMw (it's about 1:30 into the video). http://www.nytimes.com/2012/08/26/business/book-reviewers-for-hire-meet-a-demand-for-online-raves.html?_r=1&pagewanted=all is a good recent article about paid reviews. In Google's world, we take paid links that pass PageRank as seriously as Amazon would take paid reviews without disclosure or as your newspaper would treat a reporter who was paid to link to a website in an article without disclosing the payment."
Finally, below is a video recording of a Google Webmaster Central English office-hours Hangout -- the discussions involved:
- links & PageRank aren't everything; we use over 200 factors in our crawling, indexing, and ranking algorithms.
- sometimes theoretical discussions lose track of practical issues.
Here is the video that Cutts mentioned above: