rowtc2 - 7:50 pm on Feb 26, 2011 (gmt 0)
@jdn123 you can use Google AdWords: Ad Preview Tool (search words on google) , select .com and United States.
Many sites are affected and I think is not about a recent activity of a webmaster building links etc. Also, since pages dropped seriously in serps looks like a filter.
Now my thoughts are to on page elements: structure of page, repetitive elements on each page, internal linking, keyword density, external links. But looking at competitors, we usually have similar seo settings, some of them are not affected. Even i have added reviews, images,tutorials and ranking better than them before this algo change, they rank now better with no original content.