Community Managers as in the guys who manage Telegram, BitcoinTalk and Reddit for different blockchain projects.
The best way to know is ask them directly or you can check out offers on the services section on how much the ICO devs are offering to their managers. I've seen one for a telegram channel -$300 / week. That's already a good rate for moderating the whole project's channel.
Go check their bitcoin address on their profile from there you can see how much does a bitcointalk staff receive for their work.
This is another way but there's no guarantee that it came from their salary to the time they rendered for doing their job. But if you are familiar with the address who sent it to them, you can verify it alone.