Hosting websites or web apps online involves risks like free trial abuse, where users create multiple accounts to exploit free trials. Browser fingerprinting helps combat this by generating unique signatures for each browser accessing the site, using methods like canvas and audio fingerprinting to gather device-specific data like operating system and screen resolution. This technique is more accurate than cookies or IP addresses, as it is difficult for users to alter their browser's fingerprint. The article demonstrates incorporating fingerprinting in an ASP.NET web app using Fingerprint to generate and store browser fingerprints, preventing multiple account registrations from the same browser. The process involves installing necessary .NET extensions, setting up an application with database configurations, and customizing registration pages to include fingerprinting scripts. It also outlines backend verification using the Fingerprint Server SDK to ensure authenticity and limit account registrations based on fingerprint data. This approach bolsters security and minimizes fraudulent activities, offering a reliable alternative to cookies for user identification.