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hmmm...I went looking on your profile to see if you had listed a URL and having run your domain through Open Site Explorer, I can see that it is very likely that the bulk of your problems are coming from your site's external link profile. Here are a few more blog posts that might help you to get a clear picture of things: Penguins, Pandas and Panic at the Zoo by Dr Pete Meyers. Anchor Text Distribution: Avoiding Over Optimization by Geoff Kenyon. Bad Backlink Checking by Richard Baxter and for something a little less intense, but that can help immensely if you are trying to get a picture of your own situation, Link Removal Flowchart by Bob Meinke. Hope that helps, Sha P.S. The Google Algorithm Change History can also be very useful in checking whether changes in site traffic, rankings etc coincide with changes at Google.