Last year Google added an option for advertisers that they could pay a different price for search clicks and content network Adsense clicks...they also lowered the minimum bid to $0.01...before if an advertiser wanted to bid a high price for all his keywords like for example $1.00 per search click, he would also be forced to pay $1.00 per click for all his content network/Adsense clicks...now he can pay $1.00 for search clicks on $0.01 for Adsense clicks...many advertisers have lowered their prices for content network/Adsense clicks since they know these clicks are lower quality and do not convert as well as search clicks.

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