Content filtering is a cybersecurity technique used to monitor, screen, and restrict access to certain types of digital content, such as websites, emails, or files, based on predefined rules or policies. Its primary purpose is to block inappropriate, harmful, or malicious material - such as adult content, malware, or phishing attempts - from reaching users. Organizations, schools, and individuals use content filtering to protect sensitive information, comply with regulations, and create safer online environments. Filters can be applied at various levels, including network, device, or application, and are customizable to suit specific needs or user groups.