I heard that its okay to put external link such as youtube link on your site, but not Affiliate link. One of my friend site got banned from google search engine after making $3000 per month from adsense. He is still not sure the reason why he got banned, but he assumed its because of an excessive Amazon affiliate links. Lets say he has 1500 posts, 1450 posts contain amazon affiliate links, no follow, Can it be possible? Can someone clear this up? It's okay to put youtube link on every post, right? But not "Affiliate link"? and how google differentiate those link? thanks