Hey, I'm pretty new to this whole Get Paid business to. But I've done some homework, so I'll try and provide you some help.

The banners and paid e-mails cost money to make use of. Many programs offer the choice of redeeming unrequested money for ads, which you can use to advertise your referral link.
What are referrals?
Many programs offer incentives for people who get new people to sign up for their program. When somebody signs up for a program and has you entered as their referrer they become a part of your "downline".
What is a downline?
A downline is the term that is used for all of the people who have signed up under a program with you as their referrer. There are usually different levels of referral. Level 1 is simply the people who signed up with you as their referrer. And level 2 therefore is the people who have signed up under that person who had you as their referer. So not only do you get incentive for people you refer, you get incentive for the people that the person who signed up under you as their referrer.
You said that you e-mailed people and haven't gotten any replies yet? Well, be patient. If you are e-mailing the webmaster of one of the programs they are usually quite busy, and get tons of e-mails a day. But you will eventually get a reply from them. I'm not really sure what else to say, but if you need any clarification or more information feel free to provide a reply.

And welcome to the world of Get Paid.

Hope this was somewhat useful to you.