menial - 5:26 am on Nov 3, 2007 (gmt 0)
However, even if this was true...Let's say you rank #1 for 100 phrases in your industry. Why not prop up your traffic, or sales by bidding on keywords that you DON'T rank for? That way, if you are worried, this would be one safe option so as not to affect your organic ranks.
My theory (speculation) is that when you are into Adwords for a particular keyword (or set of keywords), your chances of getting high natural rankings for these keywords in the future are much harder to achieve. Google's algo relies heavily on your site and keyword's history; if a keyword associated with your domain was used as paid advertisement in the past it means your site is more likely to use paid advertisement (Adwords) in the future than a site that has never used Adwords. It makes a business sense - it's easier to sell something to an old client than to find a totally new client.