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First, I have to second Marie - the easiest way right now to detect a Penguin drop is to look at the publicly released update dates and compare them to your search traffic. Penguin often hits hard and fast - it's not usually subtle. One thing I think you have to be careful about is your definition of "quality" vs. Google's. For example, diversity matters to Google. If you guest blog on generally decent sites (non-spammy, for lack of a better word), but that's your only link-building tactic, you could still be in trouble. It's just not natural, in Google's eyes, and they're going to think you're only guest blogging to get links (which may be the truth). It's not that your posts are bad, but you're relying too much on one tactic to the point that it could look manipulative. I'm not saying this is what you're doing - just making a general observation (and one that affects a lot of people right now, IMO). At first glance (and, please note, link profile analysis can be tricky), I'm seeing a lot of keyword-loaded anchor text. It's a bit tricky, since you have an EMD (so your "brand" is keyword-based), but you may be pushing the variants of "banner(s)" too hard. Again, that can be a sign of artificial link building patterns. Frankly, you've also got some links that look outright spammy. Take this one, for example: http://www.constructionindustryscheme.org/ Your link is at the bottom (not even really in a footer) with no context or relevance to the page. This looks incredibly artificial.

Not 100% sure if it's Penguin per se but it's definitely a link based problem. Look at all of the top anchor text to the site - it's entirely commercial keywords --> http://screencast.com/t/gt4zbWiWNxMc What I've seen happen in this cases is that you will artificially rank well for some of those keywords for a little while and then a link algo catches up with you and you'll drop to where you should have been (or lower) all along. Your on-site isn't as poorly over-optimized as other sites I've seen, but it could be toned down a little but removing keyword repetition / stuffing in the titles/URLs/descriptions etc. You should definitely try to change the anchor text on any of the back links that might be good links, but just too optimized from an anchor standpoint. Use natural non-exact match anchors or branded / domain for the anchor text. For any links that are just plain old bad/spammy/low quality - try to remove them or disavow them.

in essence it tells Google it is that page so removes it from the index

Hey Gerry, Sorry for the delayed reply. The Q&A questions only get directly assigned to the Help Team if they are marked as a product support question. I just looked into the campaign associated with this account and I don't see that we have been reporting any 404 errors on this site, but I do see that the campaign was just created on Nov 26th, so it seems that you may have deleted and recreated the campaign. Since we are no longer reporting any 404s, I can't look into the issue directly now, but if you run into this issue again, I would recommend sending an email directly to help@moz.com so we can investigate what may be causing the issue. Let me know if you have any other questions in the meantime. Chiaryn Moz Help Team