I’ve been noticing blog and forum posts talking about their adsense earnings dropping. Sometimes 
the clicks are still coming in at a good pace but the price earned per click has dropped considerably.
I’ve talked about this here before but I think the noise is rising about income per click dropping, so I’ll mention it again.
Do you think that adsense earnings per click will rise, level off or decrease over time? Is adsense really something to invest all your webmaster portfolio into? Adsense Earnings Dropping? » The Affiliate Marketing Blog