cdnjs is a free distributed JS library delivery service.
Google Tag Manager is a tag management system (TMS) that allows you to quickly and easily update measurement codes and related code fragments collectively known as tags on your website or mobile app.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Internet Information Services (IIS) is an extensible web server software created by Microsoft for use with the Windows NT family.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.