Google have been tweating their search algorithms this year to battle content farms and scrapers. They named this tweak Panda Update. In February of this year, they released the first version, which was aimed at lowering the rankings of content farms - i.e. eHow, ezinearticles.com, and wisegeek.com. I don’t consider my site a content farm, but I did saw a 40% decrease in traffic as soon as the new algorithm went live.
Senh: Interesting that the one site that Google supposedly targeted with their previous algorithm has almost no effect on the site's traffic.