Tbd who's sorrier to see this development -- Slack or the Microsoft Yammer team
"Skype Teams is going to be Microsoft’s take on messaging apps for teams. Skype Teams will include a lot of similar features which you’ll find on Slack. For example, Skype Teams will allow you to chat in different groups within a team, also known as “channels”. Additionally, users will be able to talk to each other via Direct Messages on Skype Teams.Exclusive: Microsoft working on Skype Teams, its own Slack competitor - MSPoweruser
Skype Teams will also feature Threaded Conversations, which is a major feature that’s lacking on Slack. With Threaded Conversations, you can simply reply to a message on a channel by clicking on the reply button and anyone else can join the thread whenever they want — just like Facebook Comments, or Disqus Comments."