From aggressive link building campaigns to outbound links pointing to bad sites, Google search engine penalties are alive and well. And we certainly can learn something from those that have been penalized and recovered from such penalties.
In September of 2007, there were quite a few Web Directories that were hit with a penalty. The penalty caused even their site names to be nearly dropped from the Google index. There was quite a bit of buzz in the Webmaster community because many of the top and most respected directories could not be found in Google’s SERPS.