affiliate links = duplicate content?

affiliate links seen as doorway pages?

[coolasafanman]

I'm thinking about starting an affiliate program, using the code [domain.com?affiliateID=12345...]

Being that all of these pages with different IDs will be pointing to the same content using different URLs, could this hurt my site's rankings?

[doc_z]

This won't hurt (compared to the current situation) but PR as well as anchor text are probably wasted because they are splitted between 'different' pages (i.e., there is no disadvantage compared to the current situation but the benefit is probably smaller than it could be.) The disadvantage for PR isn't the major problem because PR is distriubuted from the 'different' pages to the resr of your site. However, anchor text is probably splitted between the different pages. Therefore, I would link to the same page.

If there are dublicate pages, Google normally will remove all of them except for one from the index. Sometimes Google know that these pages are the same and merge them. However, this doesn't work always and take time.