Why you need an affiliate program
Basically the idea is that affiliate sites are more likely to write positive reviews about products that they can make a commission on. If your product is up for review against another product that doesn’t offer an affiliate program it’s clear which one the affiliate site is going to recommend.
Whilst this is great for brand and reputation management the main reason you need an affiliate program is to get links.
With Google cracking down on paid links it is becoming almost impossible for commercial sites to build links outside the normal directory type of sites. If your site has an affiliate program you give sites an incentive to link to you. The best thing about these links is that they are not usually sitewide and often come in the content area of high value pages.
Do affiliate links count?
Yes and no. Some affiliate links will not help you at all. For example if you manage your affiliate program using Commission Junction the links will not pass weight. Google has probably created an algorithm to devalue most affiliate links from major programs such as CJ & Trade Doubler.
The best way to make sure your affiliate links pass weight is to manage your own program and to make sure you set it up in the right way.
For example if the affiliate link uses the format www.mywebsite.com/index.php?affiliate=1234 then it would be quite easy for Google to spot that it is an affiliate link. My suggestion would be to use something like www.mywebsite.com/index.php/1234 and use htaccess to rewrite the page to the first version. I won’t go into detail about how to do the rewrite as it will vary too much from site to site.
The next key issue is to make sure you redirect the www.mywebsite.com/index.php/1234 page to your homepage or whatever landing page you want to use. That way you are building links to the homepage rather than creating a load of extra pages with referral id’s at the end.
Before you redirect to the homepage you would need to set your affiliate cookie otherwise the sales won’t be tracked.
Loads of links
An affiliate program makes it so easy to build links its scary. You can send out emails to people saying “Please link to my site, we will offer x% commission on all products sold via your link” and get almost a 100% success rate if the emails are targeted enough.