SpyFu is a digital marketing tool that helps businesses analyze their competitors' online strategies. It provides insights into keywords that competitors are using for search engine optimization (SEO) and pay-per-click (PPC) advertising. Users can discover which keywords drive traffic to their competitors' websites and how much they spend on ads. Additionally, SpyFu offers features like backlink analysis and domain comparisons, allowing users to evaluate their own performance against others in their industry. This information can help businesses refine their marketing strategies and improve their online visibility, ultimately leading to increased traffic and sales.