Discourse is an open-source internet forum and mailing list management software application.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
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.
UptimeRobot is a web-based software that is designed to monitor the sites frequently to check whether any site is down owing to server problem or any bug in coding.