Which algorithmic approach is NOT commonly used in e-commerce product recommendation systems?

Online retailers use sophisticated algorithms to personalize your shopping experience, showing you products you're more likely to buy. These recommendation engines have become essential tools in modern e-commerce strategy, significantly boosting conversion rates and average order values. But how well do you understand what powers these personalized recommendations that seem to know what you want before you do?

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Quantum Resonance Analysis (QRA)
Collaborative Filtering (analyzing behavior patterns across similar users)
Content-Based Filtering (analyzing item attributes and user preferences)
Association Rule Mining (frequently bought together patterns)