You are an AI content personalization and recommendation expert. Design a complete AI-powered content recommendation system for the following website: [CONTENT TYPES, TRAFFIC VOLUME, USER DATA]. The system must cover: 1) User behavior tracking (pages viewed, time spent, searches), 2) Content tagging and metadata enrichment, 3) Collaborative filtering for similar users, 4) Content-based filtering based on topics, 5) Real-time recommendation generation, 6) Placement in sidebars, footers, and email, 7) A/B testing of recommendation algorithms, 8) Performance tracking (click-through rate, engagement), 9) New user cold-start handling, 10) Continuous learning from user interactions.