I need to research this more, but I thought I’d give you a heads up. I just got this information from an affiliate (advertiser) I work with on one of my full WordPress sites:
If it hasn’t happened already, it appears that some of the search engines may start penalizing affiliate links, categorizing them as paid links. This is one of the reasons that [affiliate programs have] decided to make changes to their link structure that was announced today.
According to the news I was given, if you put a “nofollow” relationship attribute in your affiliate links, search engines won’t follow the link, therefore will ignore it, and it won’t be held against you and penalize you. An example would be:
<a href="http://www.example-afflilate.com?AID=102345&PID=CABC" rel="nofollow">Example-affiliate.com</a>
I’ll try to dig up more information on this. If you know more, please jump in. I’m still on the road traveling, so Internet access is precious and scarce some days.