By default each stack has a chat channel that allows viewers (and the author) to post questions, comments and answers that attach to the stack. The chat channel is a single discussion thread.
Viewers of your stack can view and contribute to the chat by tapping on the chat icon when they are viewing your stack. They will be asked to sign-in if they are not already signed in. If they do not have an account then they can sign-in using one of the social media routes or by creating a new Learning Toolbox account. If the viewer is signed in, then the counter on the chat icon shows the number of unread chat messages.
Viewers (and the author) of the stack can receive notifications on their mobile device when a new chat message is added to one of their favourite stacks. To enable this they must have installed the Learning Toolbox app on their mobile device and accepted notifications when it was installed. They must also have favourited the stack.
This chat discussion is public – viewable by anyone who looks at the stack. The author can choose to turn off the chat channel if they do not wish to allow discussion around the stack. This is done in the stack editor.