Google Analytics is a free web analytics service that tracks and reports website traffic.
Gravatar is a service for providing globally unique avatars.
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.
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.
Vue.js is an open-source model–view–viewmodel JavaScript framework for building user interfaces and single-page applications.