A quick scan of Google's, "Webmaster Guidelines" pertains to programs that automatically submit your site to the search engines, or check rankings. I personally use them SEO Elite, but happen to doing so for years without any problems and, of course, I have my Google API Key (back when Google was still handing those out). That makes it unlikely being that. Almost always there is duplicate content of course, but all my content was brand, spanking new, and most of the articles were long, such that also designed a template issue seem probably not going. And I certainly wasn't doing anything with viruses, trojans, doorway pages, etc. Design, content and article technical guidelines are even more ambiguous. I mean we are very mindful a "useful, information-rich site" when we view one, link but it's still somewhat subjective.
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