An affiliate banner exchange program allows you to display banners on your web site in return for having your banner(s) shown on other members' web sites around the Internet. Many such programs offer extra credits or higher impression-to-display ratios if you refer new members, which is where the term "affiliate" comes in.
If you know of an effective banner exchange program, please contact Us (Dave And Jordan Lear) and I will sign up under you, test the program, and report the results here. I haven't found any good ones yet!
I tried eBannerTraffic.com but I ended up with a 1:10 ratio, i.e., I had to show ten (10) of their banners on my web site before they would show one (1) of my banners on another member's site.