Pay-per-click advertising is an online advertising model and a significant research concept within digital marketing, information systems, and online economics. It fundamentally operates on a mechanism where advertisers compensate publishers (such as search engines or social media platforms) only when a user clicks on their displayed advertisement. As an academic domain, research in this area investigates the economic principles and algorithmic mechanisms governing ad auctions, the optimization of targeting and bidding strategies, the influence of ad design and placement on user behavior, the integration of PPC with other digital marketing channels, and its overall impact on market dynamics and firm performance. Its significance derives from its status as a pervasive and economically impactful digital advertising paradigm.