Kafka is a high-throughput distributed messaging system developed by LinkedIn, designed to handle real-time data feeds and stream processing with features like low latency and fault tolerance. It supports extensive messaging needs for over 1,000 companies, including major firms like Netflix and Uber, and processes over 1.3 trillion messages daily, showcasing its scalability and performance. At LinkedIn, Kafka is utilized for various applications, such as monitoring, user tracking, and notification systems, while operating on a robust infrastructure with specific hardware configurations.