cdnjs is a free distributed JS library delivery service.
Google Analytics is a free web analytics service that tracks and reports website traffic.
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.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.
Squarespace Commerce is an ecommerce platform designed to facilitate the creation of websites and online stores, with domain registration and web hosting included.
Squarespace provides Software-as-a-Service (SaaS) for website building and hosting, and allows users to use pre-built website templates.
A modest JavaScript framework for the HTML you already have.
Twitter is a 'microblogging' system that allows you to send and receive short posts called tweets.
Typekit is an online service which offers a subscription library of fonts.