Piggybacking in the context of pop-up ads and affiliate marketing refers to the practice of attaching unauthorized or hidden ads onto legitimate traffic or websites. This typically involves injecting pop-up advertisements through malicious scripts or software without the site owner's consent. The goal is to redirect users to affiliate offers, allowing the perpetrator to earn commissions fraudulently. Piggybacking often exploits vulnerabilities in browsers, plug-ins, or ad networks, and can degrade user experience, damage brand trust, and violate affiliate program terms. It's considered a black-hat tactic and is closely monitored by reputable affiliate programs. Businesses combat this practice using anti-malware tools, secure coding, and monitoring for abnormal traffic behavior. Stopping piggybacking is crucial for maintaining ethical standards and ad integrity.