I have had months where I have been paid almost $700 dollars, however RIGHT after making a lot of money my sites all of sudden have such low eCPM's. I keep the same impressions and clicks, but right after a successful month, my site does really poor. Poor meaning around 350-400. Is this a trend? www.chicitysports.com www.vsndaily.com www.cubs2011schedule.com www.chicagosportsforums.com are my websites, if this helps. Any tips on how I can increase my earnings? I have a LOT of traffic.
According to my knowledge google has changed the policy. Google need quality not quantity. This can be the reason for the decline of your income.
Do your ads are relevant to your niche? If not then read this page regarding how to tell Adsense for showing relevant ads. Hope it will help you.
Nice looking sites. Went to the cisports one and noticed that a lot of your content is the same as http://www.upi.com/. Is that your site too? I mean word for word.
Drop in eCPM would be of various reasons, one probably a drop in advertisers or lower placement bid in the niche. Do a check at spyfu.com see any difference comparing with your good month. Cheers