Sites with a lot of thin content may receive a message in the Manual Actions page of Google Search Console, stating that low quality content has been detected. Google lists a number of different types of pages which typically include thin content:
Automatically-generated content – Text which is generated programmatically by a variety of methods, including scraping RSS feeds, auto-translated text and nonsense text stuffed with keywords.
Thin affiliate pages – Low value and duplicate pages referring someone to a product or service on another site.
Thin syndication – Scraped content or low-quality guest blog posts.
Doorway pages – Very similar pages changed slightly to rank for a different phrase with each one e.g. to rank for a different location.
Pages, like the ones listed above, are considered webspam and go against Google’s webmaster guidelines, meaning that they may receive a manual action that removes part or the whole of a site from the index.