Yield aggregators are platforms that help users maximize their returns on investments in the cryptocurrency space. They automatically move funds between different DeFi protocols to find the best interest rates and yield opportunities. This process allows users to earn passive income without having to constantly monitor the market. By pooling funds from multiple investors, yield aggregators can access larger investment opportunities and negotiate better rates. They often use strategies like liquidity mining and staking to generate higher yields. Overall, yield aggregators simplify the investment process and enhance potential returns for users.