cdnjs is a free distributed JS library delivery service.
Google Analytics is a free web analytics service that tracks and reports website traffic.
Naver Maps help develop location-based services which provided by Naver.
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.
Ubuntu is a free and open-source operating system on Linux for the enterprise server, desktop, cloud, and IoT.