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.
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.
SimplyCast is an all in one marketing suite for organizations worldwide. SimplyCast's software automates email, survey, event, SMS, fax, Twitter and autoresponder marketing in order for businesses to effectively reach customers on their preferred mode of communication.
VerticalResponse is to let user create, send and track professional-looking emails quickly and affordably. The tool take the work out of email creation and guide user through, step-by-step on how to use one of their 700 professional, pre-designed email templates.