LAMP stack is popular because it is a powerful open-source web development platform that is free, flexible, and customizable. The LAMP stack consists of four components: Linux (operating system), Apache (webserver), MySQL (database management system), and PHP (programming language). Together, these components provide a stable and reliable environment for developing and deploying web applications. LAMP stack's popularity can also be attributed to its ease of use, wide community support, and the availability of a large number of pre-built applications and libraries. Additionally, the LAMP stack is cross-platform compatible, making it an ideal choice for developers who work with different operating systems.