Google announced that AdWords advertisers will be able to run campaigns in the AdMob network, a development that was expected since Google acquired AdMob for $750 million two years ago. In the last two years there was a big gap between AdWords, which offered traditional Web based adverts and AdMob which offered mobile ads on smartphone applications. Since more and more HTML5 based cross platform apps appear on the market, it was necessary to offer mobile ads also for these apps.
I also experienced that the value of AdWords ad clicks decreased dramatically, while the mobile ads boomed and brought more money per click, but that was just my impression.
Now both, mobile ads and Web based ads are coming together again and i am sure within the next years the revenu of mobile ads will also drop a lot.