The purpose of the HTTP protocol in web communication is to define how messages are formatted and transmitted over the internet. It enables the transfer of data between clients, such as web browsers, and servers, facilitating the display of web pages. By using methods like GET and POST, HTTP allows users to request resources and submit data, ensuring interactions on the web are standardized. This protocol is integral to the functionality of the World Wide Web, allowing for a seamless user experience by connecting diverse systems and enabling access to online content globally.