After a profitable year with Yahoo and a moderately profitable period with AdCenter, they merged my accounts. Shortly thereafter, every campaign stopped serving impressions. They all went to zero. I received no warning, no advice, no information whatsoever. If I had not been checking the account daily, I never would have known. After going around and around and around with AdCenter reps for over a month, the campaigns are still shut down. I could write an eBook about it. The CSRs are almost completely clueless and their supervisors are polished but clueless. I have spent hours on the phone with these people. They accused me of everything imaginable, but they finally settled on blaming HubPages.com, which is where some of my landing pages are. They insisted that my landing pages contained too many links and did not provide an acceptable "user experience." Is anyone else using HubPages to provide a landing page?