Apache Tomcat is an open-source implementation of the Java Servlet, JavaServer Pages, Java Expression Language and WebSocket technologies.
cdnjs is a free distributed JS library delivery service.
Google AdSense is a program run by Google through which website publishers serve advertisements that are targeted to the site content and audience.
JSDelivr is a free public CDN for open-source projects. It can serve web files directly from the npm registry and GitHub repositories without any configuration.
Kakao platform provides various services such as Kakao Talk, Kakao Talk Channel, Kakao Story as well as Kakao Pay, Kakao Commerce, Kakao Page provided by the subsidiaries. Users can use all Kakao platform services with a united account called Kakao Account.
Open Graph is a protocol that is used to integrate any web page into the social graph.