Cloudflare is a web-infrastructure and website-security company, providing content-delivery-network services, DDoS mitigation, Internet security, and distributed domain-name-server services.
Facebook pixel is an analytics tool that allows you to measure the effectiveness of your advertising.
Google Analytics is a free web analytics service that tracks and reports website traffic.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Twitter is a 'microblogging' system that allows you to send and receive short posts called tweets.