That's 15000 people per month. As stated before it's easy to join. You fill out a form online and your account is automatically setup. Download some banners. Copy some html code on to your site and you are done.
Text links are okay, as long as they are honest.
Let us know. Try them all, the system tracks each banners rating. Use the ones that work for your site. Every week you are sent a check. We do not track who signs up from you.