CPA - gather knowledge how?

Can any one tell me details about CPA (cost per actions).
how it works?
who get benefited?

 

There are many CPA networks out there that you can join. But what it is anytime someone fills out an offer with their name e-mail, and phone number (basically a forum) you get paid. It depends how much you get paid though. Someone can give you their e-mail and you get paid. Try to join some CPA networks to get started..