A banner exchange program is a program designed to allow webmasters
to exchange banners (a form of bartering) to enable webmasters
to promote their sites without the outlay of cash. A program
typically allows a webmaster to display one advertisement,
across the network, for every two advertisements it hosts on
its site. Unlike a straight exchange with one entity, exchange
programs allow for the possibility for the banner to be displayed
on many web sites (those sites that participate in that particular
network).
