Please fix your push notification systems as people have to use Skype when Slack cannot get things done! Video/Screensharing should have a checkbox on your product map. Oh but you don’t have them. Damn!
addressing a single person regarding a project that has a channel: should I write in a PM or in the channel?
In the PM I have to explain the context, it's hard to find it again because you will be looking for it in the channel and slack artificially blocks easily sharing the information to a third.
In the channel I force the whole team to read my things that are quite irrelevant to them, in the worst case a small 1 on 1 debate will ring notifications for 10 minutes. If the rest of the team ignores them they also ignore any other notification that might jump in between.
Or turn channel notifications off and only work with mentions? But than it would need some education to keep mentioning, even in huge IRC channels you sometimes forget...
MS has been battling with Evernote by OneNote, Gsuite by Office 365, IFTTT by Flow, Dropbox by OneDrive, Facebook by Linkdin, Scribd by Docs or Sway, any to do apps by Wunderlist, Google by Bing, Google Hangouts by Skype, MacBook Pro or Chromebook by Surface etc. Looking at this picture, Slack's staff realizes the need to show their courage and capabilities to their users by this open letter. May be it is an attempt to gain empathy and have more loyal happy users.
I am not sure but MS will be professional about his decisions and ignore this letter.
I don't consider Slack to be an open platform...