Cloudflare is a web-infrastructure and website-security company, providing content-delivery-network services, DDoS mitigation, Internet security, and distributed domain-name-server services.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Squarespace Commerce is an ecommerce platform designed to facilitate the creation of websites and online stores, with domain registration and web hosting included.
Typekit is an online service which offers a subscription library of fonts.