With the latest Penguin Update Google has caused some unrest among SEOs und web site owners. With the updates by Panda and Penguin the evaluation of backlinks was introduced and tightened and the criteria for incoming links seems to be composed much more strictly.
For a long time it appeared that the number of backlinks was crucial for the Off-Page Optimization. The impact of this was a veritable market for back links. Some service providers offered, and still offer, providing back links which bring forward its page ranking in Google. Some SEO services diligently build so-called satellite built pages whose only function was to provide links to the main page of the customer. Google’s action against this tactic in May, 2006, caused a sensation as BMW was placed on a blacklist and the page rank set to 0 by Google. BMW had previously tried with so-called doorway pages, which were packed with keywords, to steer traffic to its website in the search results for used cars. (See:BMW given Google ‘death penalty’)
Abuse through Spam-Links
In the most recent updates, Google values inbound links more strongly. Thus, links from well ranked sites in a relevant context lead to a better assessment by Google. What is new, however, is that bad back links lead to a downgrade. This approach is not totally unproblematic, as the operator of the linked site does not normally has control over incoming links. There are already reports of extortion, in which this mechanism is exploited. In a notable case, a wooden toy discounter was the target of such extortion and was heavily damaged by spam links. (See: Ranking: Wie ein Erpresser einem Onlineshop schadete)