What's up with PPI

Which networks are still operating and which ones are better there used to be good choice like Revenyou, Installerex, Amonetize now looks like installerex and revenyou are dead what's left?

Google closed the industry, they started with the big ones like Installerex so the only one left today are very small that are not even on Google's radar. Everyone switched to CPM, me included. I'm working with Ad-Maven which is owned by the same company that used to own Installerex, so I know they are legit.