A Google penalty may be imposed when a website violates Google’s Webmaster guidelines and spam policies or employs “black-hat” SEO techniques to boost their rankings unethically. These penalties can be algorithmic, triggered by automated systems, or manual, issued by human reviewers. Other reasons for penalties include keyword stuffing, poor-quality links (both inbound and outbound), thin or low-quality content, cloaking, hidden text or links, and spammy practices.