Content clicks may be priced differently than search clicks. Using smart pricing, AdWords automatically adjusts the cost of clicks for keyword-targeted ads that appear on content network pages. While you set one CPC bid, if our data shows that a click from a content page is less likely to turn into actionable business results � such as online sales, registrations, phone calls, or newsletter signups � we reduce the price you pay for that click.
#*$!? How can google, possibly know, whether an ad clicked on my site, resulted in a phone call?
Now I know they're clever but they're not magic.
So given this snippet of information, it kinda makes sense that google have done something to my account, since it was wrongfully suspended a few months ago. Since the suspension my eCPM has been lower.