Telegram CEO reveals their plans on adding voice calling into the app in one of his tweets. Previously they said in April 2015 that they had developed “encrypted voice calling technology some time ago,” but never prioritized the technology. I hope it’ll work as stable and fast as the main messaging functionality.

http://venturebeat.com/2017/01/17/telegram-ceo-says-messaging-app-will-add-voice-calling/

About 2-3 years ago I was using a couple of services where you can select a language and find a foreigner to practice and master different languages. I remember how hard it is to find person available at the same timezone and willing to discuss topics you want to discuss. And today I’ve come across a review of Duolingo’s chatbot which can help you to learn desired language. Clear benefits: 24/7 available conversationalist, relevancy - it suggests you to discuss topics which are popular at the moment (USA President election for example), gamification - you can gain XP points for every correct sentence and ask help when you don’t know what to say. Right now it has some restrictions in terms of vocabulary and accepting written responses only, but I’m sure that this is the future and with AI and speech recognition technology evolving it will be a very popular way to learn a new language - talking to a bot which corrects your pronunciation and help you to form written responses.
https://www.youtube.com/watch?v=M7sm33TSfUQ

Statsbot.co (top1 bot for Slack which allows you to get analytics data by asking a natural language question) lately published a story about their journey to success. They told about how they monetize Statsbot, built a business on Slack and got hired by over 20,000 teams. In the article you can find their thoughts on different business models for bots in Slack and their recommendations on using different 3rd party tools to speed up your bot development.

https://medium.com/stats-and-bots/how-statsbot-is-building-a-business-on-slack-d0d4ca1655b#.bc6yg4wmm

Facebook replaces its old inbox with the web version of Messenger. It can sound like not a big deal for you, but it really is and let me explain why. Before that Facebook had 2 versions of messaging UI: old crappy one without support of all the bot features (quick replies, location and many more) and the second one which was a Messenger UI - with support of all the features you need to get the full experience of bots. And now Facebook redirects you directly to the Messenger when you want to open your inbox. It’s a huge step to the unification of conversational experience for Facebook users and minus 100XP points of pain for all the bot developers.
https://techcrunch.com/2017/01/18/facebook-replaces-its-old-inbox-with-the-web-version-of-messenger/