Google Sign-In is a secure authentication system that reduces the burden of login for users, by enabling them to sign in with their Google account.
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.
VK is a Russian online social media and social networking service.
WordPress is a free and open-source content management system written in PHP and paired with a MySQL or MariaDB database. Features include a plugin architecture and a template system.