"There is a looming realization of Google controlling the majority of online advertising" If you use another ppc provider on your page, you might get penalties

"There is a looming realization of Google controlling the majority of online advertising" If you use another ppc provider on your page, you might get penalties affecting your ranks http://support.google.com/webmasters/bin/answer.py?hl=en&answer=66361 http://support.google.com/webmasters/bin/answer.py?hl=en&#38... Similar with affiliate links, http://support.google.com/webmasters/bin/answer.py?hl=en&answer=76465 http://support.google.com/webmasters/bin/answer.py?hl=en&#38... Even though that's worst case scenario and might be a bit tendentious; there's no clear way to interpret what you can or can't do, or how google might interpret it.