Review aggregators are online platforms that collect and display reviews and ratings from various sources about products, services, or businesses. They help consumers make informed decisions by providing a summary of opinions from multiple reviewers in one place. Popular examples include Yelp, TripAdvisor, and Rotten Tomatoes. These platforms often use algorithms to compile and analyze reviews, offering an overall score or rating based on user feedback. This allows users to quickly assess the quality of a product or service without having to sift through numerous individual reviews.