I’ve been playing out with Google adsense settings for some time now and found out many interesting things on the go! However this post is not that much complicated or super informative, just a simple thing that I noticed and thought to share!
Well, I blocked all Google certified ad networks a month or so ago and it worked all fine until this month when my Google adsense income suddenly dropped markedly! so at that time I enabled my google certified ad networks and also removed the competitive ad filter from my Google Adsense account which lead the adsense income go back almost upto 40% . 
When I enabled the Google certified ad networks in my adsense account settings, I over looked the option to Automatically block new Google certified ad networks and left it turned on. If you want to enable all new Google certified ad networks, you may need to untick this option so that you don’t lose any new ad network ads!