AWS ELB is a network load balancer service provided by Amazon Web Services for distributing traffic across multiple targets, such as Amazon EC2 instances, containers, IP addresses, and Lambda functions.
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.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.