You can now keep your conversations focused on a new channel moderation feature. This feature will allow the team owners and members exclusive rights to create a new post in the channel and control whether team members can reply or not. Think of this as a focus feature. It will allow your owners and members to stay focused and on topic.

So what can channel moderators do? Channel moderators can:

• Start new posts in the channel. When moderation is turned on for a channel, only moderators can start new posts in that channel.
• Add and remove team members as moderators to a channel. Keep in mind that by default, team owners are channel moderators and can’t be removed.
• Control whether team members can reply to existing channel messages and whether bots and connectors can submit channel messages.

Learn more about channel moderation in this Microsoft support article.