Rumble

Rumble is a completely off-the-grid application and delay-tolerant
micro-blogging application that allows a device to connect, chat and share
content (text and images) with other people around you. It doesn't require
Internet to work and rely instead on Smartphone, Local Area Network (Bluetooth
and Wifi) and human mobility to spread information.

Using only the social fabric as an infrastructure, it makes Rumble suitable for
use case where the Internet is either best to avoid (surveillance/censorship) or
simply not available.