There are a lot of Telegram crypto related groups with people that don't even familiar with Steem. everytime I'm seeing someone asks what is Steem and why it gained so much, I tell them about it and they get really interested, because of the idea of Steem.
I think Telegram can alternatively work on top of Steem, because it can also promote Steem.
I think it's viable and will last for long. I'm a part of some groups, I'm not active much, but it can be valuable. they can send an announcement that will change the price of the coin massively ( happened for me with MOD, made a lot of satoshi. )
I think it can leverage, for sure.
Oh, and btw, the Telegram ICO? INSANE. heard about it yesterday.