Amazon S3 or Amazon Simple Storage Service is a service offered by Amazon Web Services (AWS) that provides object storage through a web service interface.
Fastly is a cloud computing services provider. Fastly's cloud platform provides a content delivery network, Internet security services, load balancing, and video & streaming services.
GitHub Pages is a static site hosting service.
MathJax is a cross-browser JavaScript library that displays mathematical notation in web browsers, using MathML, LaTeX and ASCIIMathML markup.
Varnish is a reverse caching proxy.