This is my ADC entry.
Automate is an automation software for Android, similar to Automator on MacOS or pipes on UNIX platforms. (output of an action is the input of the next action)
There are small programs called actions for everything you can do with your mobile phone. You can create workflows using these actions to get time consuming activities done with a single click.
People usually use their phones outside, driving or walking, while trying to catch a bus etc...
It is hard to take a picture, browse to your webalbum, select the picture you have taken , click the upload button... or record a video , upload it to youtube, tell it to your friends. With Automate you can achieve these kind of things without doing the same actions over and over again. Just create a workflow for it.
Also every Android developer can create their own actions using Android SDK. For example developer of an image editing software can provide actions like "resize images" or "adjust brightness".
Thanks for reading