Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
Odoo is business management software which includes CRM, ecommerce, billing, accounting, manufacturing, warehouse, project management, and inventory management.
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.