The Meta Pixel is a small piece of code placed on your website that tracks visitor actions — like page views, add-to-cart, and purchases — and sends this data back to Meta Ads Manager. This lesson covers why the Pixel is critical for ad performance: it allows Meta’s algorithm to learn who is likely to convert and optimize ad delivery toward those people, and it enables building Custom and Lookalike Audiences based on real website behavior rather than just interests or demographics.