Do You Use Affiliate Pages?
While websites uses affilate pages to earn revenue, they have chances to ruin originality in areas of reviews, ratings, product descriptions, comparisions. In another situation they may affiliate from a different product category than their own nieche.
If your website has such problems and is only built with mainly affiliate pages. search algorithm will devalue your website for sure. You will not achive better ranks because of penalties by search engines.
To regulate this problem affiliated websites must create original content for targeted audience.