tedster - 5:01 am on Dec 22, 2011 (gmt 0)
It usually takes a good deal of messing up a site to get such a penalty
From what I've seen, the most common way to get into OOP territory is to over-think what "SEO" is and then try to use every approach and tool you've ever heard about.
Most SEO advice on the web is several years out of date and it often leaves out a good bit of background context. Even worse, a lot of advice is being passed on second- and third-hand, with distortions added at every step.