Put on your tin foil hats, it's time for the most common SEO conspiracy theory: spending on search engine advertising (PPC) improves your organic SEO rankings.
In all of the experiences we've ever witnessed or heard about, this has never been proven nor has it ever been a probable explanation for effects in the organic results. Google, Yahoo! & Bing all have very effective walls in their organizations to prevent precisely this type of crossover.
At Google in particular, advertisers spending tens of millions of dollars each month have noted that even they cannot get special access or consideration from the search quality or web spam teams. So long as the existing barriers are in place and the search engines cultures maintain their separation, we believe that this will remain a myth. That said, we have seen anecdotal evidence that bidding on keywords you already organically rank for can help increase your organic click through rate.
