Google Tag Manager is a tag management system (TMS) that allows you to quickly and easily update measurement codes and related code fragments collectively known as tags on your website or mobile app.
Handlebars is a JavaScript library used to create reusable webpage templates.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
Open Graph is a protocol that is used to integrate any web page into the social graph.
PayPal is an online payments system that supports online money transfers and serves as an electronic alternative to traditional paper methods like checks and money orders.
Ruby on Rails is a server-side web application framework written in Ruby under the MIT License.
Twitter is a 'microblogging' system that allows you to send and receive short posts called tweets.