Blue sky background
You’re presented with a piece of blank white paper.

You note on it.

Publish.

The paper folds like a paper plane and flies away.

You can scroll the sky at will and grab /click on paper planes, reading the content in black and white. 

You can reply to a paper plane and it will fly together/in formation. 

No user info is displayed. But you can fold the paper plane back to a sheet to reveal who said what etc.