SEO is a very fast industry and undoubtedly one of the biggest online industry and if you look at numbers, PPC is very small compared to SEO. People are ready to spend more on SEO than in PPC. Ideally Google would love to grab their cut from the SEO spends as well and so they are making it more harder for SEO to survive. This would mean people are forced to forget SEO (Like they targeted Toolbar PR) and spend on PPC but this has turn upside down on them only.
What it has done is made people to spend less on PPC because now search is not very relevant to the keywords and may be the conversion in PPC has gone down the barrel.
I had few PPC campaigns and in September I had my worst conversions and for no reasons. There is nothing that has been done on these website or landing page in recently for such a drop in CTR on those sites and this site has no traffic from SEO and purely PPC traffic. The only reason I could associate for such a drop in conversion is because Google is sending users that are not very related to my keywords and so on October 10th 2012, I just paused all my PPC campaigns. All means All and I would like to take a break for at least 30 days before I retest things.