Updates like Panda killed many sites in 2011. The proof was provided by the British journal New Scientist in December 2011.
Search engines cut many heads off the web between April and August 2011. Rotten heads. With new filters like Panda, Google has downgraded around 10% of all sites in the world. Bing-Yahoo would have done the same. Artificial sites, stuffed with advertisements, called " content farms ».
This has just been proven by the British magazine New Scientist, in its edition of December 15, 2011. A computer scientist from the University of Glasgow, Richard McCreadie, carried out the same research in March and August 2011.
Websites riddled with ads and generic advice are gone
Example request: " how to train for a marathon ". In March, websites full of ads and generic advice like " invest in a good pair of running shoes », Appeared in the top 10 of Google. By August, they were gone. High-quality content sites like Runner's World magazine have taken their place.
Similar results were found for 50 different queries. What made the magazine say that " Google and Microsoft have won a big victory Against "ad trap" sites.