If someone goes through your links into the shop of the merchant, and buys something, you earn commission from the sale, between 5% and 40% depending on type of merchant.

Some merchants also pay for each click or each lead. A lead is a new visitor to the shop that asks for more information or prize offers.

People or companies having these links on their web-sites, are called affiliates, and the links are called affiliate links. The administrative infrastructure by the merchant that the affiliate register into, in order to get the linking code, is called an affiliate program.

To register into an affiliate program is usually free, and through the program you get freely all you need to make the linking code, to monitor the traffic through your links, and to see what commission you have earned.

An affiliate program is not a MLM program, since the affiliates only earn from sales, leads or clicks.

However, in many programs you can recruit other affiliates and earn some commission from the sales made by the recruited affiliates too.

There are also common networks operated by third-part companies where several merchants use a common software and administrative infrastructure to recruit affiliates and monitor the traffic from affiliates.

These are called affiliate networks. Both the merchants and potetial affilliates register into the network, and the affiliates can find links to the online shops of hundreds of merchants to use at their web-site. Examples of affiliate networks are Commission Junction and Clixgalore.

From my experience, the best affiliate programs are for merchants selling althernative health items or items for erotic improvements. I also have good experience with programs in the fields skincare, cosmetics and hobby.

What will work best for you, will however depend upon the kind of traffic you have, and the interests of people visiting your site.