I recently started dabbling in Google ads for my side project. And I have learnt a lot about advertising through actually running campaigns: - Different countr

I recently started dabbling in Google ads for my side project. And I have learnt a lot about advertising through actually running campaigns: - Different countries have drastically different CPA (cost per action). You can acquire users easily in low-income countries but not US or Canada. So you have to set different CPA target for different countries. Currently Google ads doesn't seem to do adjustments automatically for app campaigns. - It might take more than one impressions to convert one user. I looked at the conversion paths analysis in Google Analytics and found about 25% of conversions had two or more campaign impressions. Also there's a term called "touchpoints to conversion", basically how many interactions it took for a user to convert. Mine is about 2-3 touchpoints for all campaigns. - Running ad campaign for my app feels surprisingly similar to the experience of hyper-parameter tuning of ML models. Google in fact does use ML to run campaigns internally. That might also be the reason why the initial phase of campaign doesn't work very well with limited training data and bad initial weights.