When Google’s Penguin 4.0 update was announced on September 23rd, one of our clients had a number of key pages on its site get deindexed. Their site certainly had several technical SEO, usability and other issues, but I’d hardly classify it is “webspam” which is what Penguin purported to target. Of course as soon as the deindexation (and subsequent organic traffic drop) was identified, we jumped into action to determine the cause which we felt were mostly issues that we had previously identified.
That said, I think we missed one big issue so I am presenting it here for you to cut and paste into your SEO audit docs:
P0: Google Screwed Up Its Algorithm
Here’s the supporting documentation: