A way to earn money on YOUR website, by sharing revenue, with an online merchant.
For one link explaining the concept, click on:
http://www.wisegeek.com/what-is-affiliate-marketing.htm
And another link offering an inexpensive e-Book to download, click on:
Another link that is quite extensive is on Wikipedia:
Here’s its take on the business:
http://en.wikipedia.org/wiki/Affiliate_Marketing