SimilarWeb is a tool that allows users to analyze competitive websites by providing traffic statistics and insights. It generates a six-part report on domains that includes: 1) an overview of rankings, traffic, and sources, 2) geographic distribution, 3) referring sites, 4) keywords, 5) social media, and 6) related interests. Users can add competitors for direct comparison and discover new sites through related website recommendations. The top websites feature also identifies leaders by category and country.