The tutorial explores the use of D3.js in creating interactive and real-time graphs for web pages, specifically focusing on a Bitcoin pricing and trading infrastructure. It addresses the challenge of data staleness in web graphs, which traditionally require page reloads to update information, by integrating PubNub to allow real-time data updates without reloading the page. The guide demonstrates connecting to a live Bitcoin data stream via PubNub, transforming JSON data for visual representation, and implementing features such as brushing and tooltips for enhanced user interaction. The tutorial emphasizes the seamless integration of real-time graphing capabilities into existing D3.js applications, facilitating more informed decision-making for users through up-to-date data visualization.