...It’s an application you host on a server that uses the Slack platform and behaves however you script it to. You will first want to create a new Hubot project. The simplest way is to use your computer’s terminal app to install Yeoman, a handy tool that builds projects from a template. Slack apps are a container for many capabilities in the Slack platform, and let you access those capabilities in a single place. This is the recommended choice because it allows room for your Hubot to grow. To begin, you just need a Bot User.
...It emulates an iOS device to connect to Google Hangouts APIs, enabling messaging, status indicators, and notifications on Windows, macOS, and Linux—eliminating the need for a Chrome-based Hangouts app.