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.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Twitter Emoji is a set of open-source emoticons and emojis for Twitter, TweetDeck, and also for Android and iOS versions of the application.
Varnish is a reverse caching proxy.