has anyone build a slack-killer with it yet?
Stockflare
1

Yes.

You can build chatbots that can take any webhook and unleash into a group, supergroup or channel…. and even inline into any conversation. You can snooze and mute any of these and interact with bots in almost any way programmatically. And because there’s a telegram command line interface client available, you can build a simple script in whatever language you know to interface with anything that can run on a unix based server.

Beyond that, I find it dead easier to set up a telegram group with people I work with because there’s no real barrier to entry — there are clients available for every OS and if you know Facebook, Hangouts, WhatsApp, then you’ll already know how to navigate Telegram.

One major thing too — there are DND, mute, read-to-here indicators and status messages in Telegram, so it’s pretty easy to tell when people in a group are actively engaged or getting some downtime without bugging them…and vice-versa.