What a useless article, it just state the obvious "Experimenting with various solutions to find the ones that best match your needs is critical"
"Experiment with various" means, for each network:
1) register
2) install their sdk
3) test the app to see if the ad network is REALLY working, each ad network has specific requirements.
4) wait for ALL your users to update your app(s!) to the newest version
5) wait at least 1 month to have some meaningful data