Telegram

 Telegram  is a cross-platform encrypted messaging app. Telegram is a centralized service, with a closed source server and open source clients.

It was founded by Pavel Durov, the creator of vKontakte (the russian analogue of Facebook), and might be considered the doppelgänger of FB Messenger app.

POSSE to Telegram
Telegram supports public and private channels that can be published to via a telegram bot.

IndieWeb Examples

 * syndicates to a telegram channel using Postr

Micropub with Telegram
PostrChild has a telegram bot that allows posting to your own website using Micropub