I have been experimenting with some AdWords campaigns for my Android app, which is translated into English, German, Swedish and Danish.
First I tried a "global" one, targeting English speakers worldwide. That ended up being totally pointless and super costly, resulting in a click-through-rate of 5% but only one single app install from 61000 ad views, the majority of which were in India and Bangladesh.
Then I tried a number of smaller ads, each one targeting users in the respective "native" speaking countries - US/UK, Germany, Sweden and Denmark. Those have been more successful, resulting in anywhere from 0 (US) to 25 (Germany) installs, at a CTR of 9-17 %.
However, now I thought that it's kind of stupid to target only Germany with an app translated to German - after all, German and close dialects is spoken in many countries such as Austria, Poland, Switzerland, etc. so I tried targeting German speakers instead of the country Germany.
After a week, the results are in, and they're horrible. 88000 views, 1.9% CTR and 3 app installs, each app install having cost three times the revenue of the app. What happened? Well, once again, the ad was mostly shown in India. 18000 views in India alone, and only 172 views in Germany+Austria+Switzerland (however, funnily enough, those 3 total app installs consist of one in each of those three countries).
I have a hard time believing that there are 104 times more German speakers looking at ads in India than in Germany+Austria+Switzerland, so why is my ad being shown mostly in irrelevant countries?