How do affiliate links affect your search ranking?

If you are the one running the affiliate program, affiliate links will provide substantial backlinking on numerous websites. Search engines will not penalize you for who links to you, only who YOU link to.

With that being said, if you are associating your webpage with another webpage by creating a link to it, if a search engine either bans or penalizes that website in any way it may transfer to your site as well.

The bottom line is, if you use a reputable affiliate network the links on your page should not degrade your ranking per se, but another junk link instead of a link to relevant ranking pages may hurt you.