Web metrics can be broken into four categories: business, usability, SEO, and social media metrics. Business metrics measure revenue and ROI to determine a website's success in increasing profits. Usability metrics include metrics like returning visitors and time on site to measure a website's ease of use. SEO metrics track things like backlinks, page rank, and keywords to measure search engine optimization efforts. Finally, social media metrics track user engagement through metrics like social shares, mentions, and reviews.