Gravatar is a service for providing globally unique avatars and was created by Tom Preston-Werner. It is owned by Automattic, having integrated it into their WordPress.com blogging platform.
Hypertext Markup Language (HTML) is the standard markup language for documents designed to be displayed in a web browser. It can be assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaScript.
PHP: Hypertext Preprocessor is a server-side scripting language designed for Web development, but also used as a general-purpose programming language. PHP code may be embedded into HTML code, or it can be used in combination with various web template systems, web content management systems, and web frameworks.
Gmail is a free, advertising-supported email service offered as part of Google's G Suite, with 15GB of storage, color-coded inbox filters and unsend button.
Google Cloud DNS is a scalable, reliable and managed authoritative Domain Name System (DNS) service running on the same infrastructure as Google. It has low latency, high availability and is a cost-effective way to make user applications and services available to users.
YouTube is a video sharing service where users can watch, like, share, comment and upload their own videos. The video service can be accessed on PCs, laptops, tablets and via mobile phones.