Cloudflare is a web-infrastructure and website-security company, providing content-delivery-network services, DDoS mitigation, Internet security, and distributed domain-name-server services.
Express is a web application framework for Node.js, released as free and open-source software under the MIT License. It is designed for building web applications and APIs.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Typekit is an online service which offers a subscription library of fonts.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.