Google claims that there is no correlation between PPC and organic listings. If people would actually know or realise that there might be another truth about Adwords, then it could cause businesses no longer to advertise of course. Only this would be reason enough to proclaim that phrase.
Two reasons for my doubts about the existence of a certain correlation between both PPC and organic search:
1. Adwords usability
Google might not like recurrence of the same domain on the same resultpage because google-users can see the same domain twice on the same page. Thus, if you configure Adwords to appear on the first resultpage let’s say for “car rental Sydney”, Google will give preference to publish your advertisement instead of your unpaid, organic result (no matter how well optimized it might be). If your website would appear twice, it will give a bad userexperience for people who use Google to search. The first page is what really matters, the 2nd and third are less important as it’s the first one that is mainly used.
2. Adwords as a profit
Think with me : Google has become a big company and a big brand, only because they make money. The way money is made is not with the unpaid, natural serps. Be it a surprise that they make money with Adwords ? Why would Google place your website on the first page left-hand side (even with sufficient optimisation), and this while you simultanously pay them for an advertisement on that first page ?
Suppose Google is as honest as they claim they are (no correlation between PPC and organic). Then Google would not interfere with the natural listings, even for advertisers. What would happen next is that when a website appears on the first page (organic), then the advertiser would most likely stop advertising (for that keyphrase or for the entire PPC-campaign) because the website IS on that first page already (why put an extra advertisement in that case ?!). Result is that advertisers would most likeley stop advertising as soon as they reach the first page with organic. Hence, Google would loose business due to organic, free listing. Do you really think that is not measured and influenced by Google (it’s their core-business btw.) ?
An interesting article :
http://www.seroundtable.com/archives/013662.html