Cloudflare is a web-infrastructure and website-security company, providing content-delivery-network services, DDoS mitigation, Internet security, and distributed domain-name-server services.

reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.

jQuery is a JavaScript library which is a free, open-source software designed to simplify HTML DOM tree traversal and manipulation, as well as event handling, CSS animation, and Ajax.

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.

Bootstrap is a free and open-source CSS framework directed at responsive, mobile-first front-end web development. It contains CSS and JavaScript-based design templates for typography, forms, buttons, navigation, and other interface components.

YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.

Google Analytics is a free web analytics service that tracks and reports website traffic.

Vue.js is an open-source model–view–viewmodel JavaScript framework for building user interfaces and single-page applications.

cdnjs is a free distributed JS library delivery service.

Popper is a positioning engine, its purpose is to calculate the position of an element to make it possible to position it near a given reference element.

ShareThis provides free engagement and growth tools (e.g., share buttons, follow buttons, and reaction buttons) for site owners.