Dont put no-follow if the people your affiliating with dont know about it. Thats bad business. You will get backlinks for your affiliate links ( conicdering that they return the links on their site )
Affiliate links not harm to the site.. and even if u add nofollow tooo google will understating that its cookie filling
Showing affiliate links on your site would not make any harm to your site in terms of ranking. However it would be considered as your business partners
You should use NoFollow, redirects and whatnot to hide them. Google doesn't like affiliate links. Maybe because they're too commercial
You can use this bit of Javascript <a href="http://URL THAT NEEDS TO BE SHOWN" onclick="parent.location.href='http://URL WITH REFER ID'; return event.returnValue=false">ANCHOR TEXT HERE</a>, Code (markup): It works for me! Greetz
use nofollow on affiliate links or you can use redirection through another internal page. for example, once someone clicks on an affiliate link, say download video, then you can have another blank page created with filename download-video.htm or something where you use html redirection to direct the page to your affiliate site. second method is used my affiliate marketers to install tracking code on the page to detremin who clicked on the link, where did they come from, whether that click converted or not, etc. but if you want to keep it simple, just add nofollow