Not really a dupe, since it's a link to the official Gitter blog instead of Venturebeats
What is the use of Gitter with Gitlab, in the post-slack world?
Huge gitter user here. We have still found it more seamless for our open source community over slack. A big reason for this is due to the model of how easily gitter enables people to join rooms.
Our community has over 4k users in the channel.
Slack still seems to be more focused on internal companies not communities with lots of people.