The IntelliGantt Web Part integrates with SharePoint Discussion Lists within the same SharePoint site.
A SharePoint site is typically created with a Discussion List called 'Team Discussion'.
To link a task with a Discussion topic, first open the tool window by clicking on the blue circle at the very upper left of the IntelliGantt Web Part.
Click on the 'mini caption' icon to create the topic.
A popup dialog appears seeded with the task name for the discussion topic. Type in the text of your discussion in the multiline text box.
The new topic is now in the Team Discussion.
Click on the new topic in the discussion to see the root of the new thread.
The topic can also link to the task by adding a lookup column called 'Task', as seen here in the topic properties. (Technical Details)
Back in the IntelliGantt Web Part, the task can also link to the topic by adding a lookup column called 'Discussions'. When you move the mouse over a discussion entry in the task list, a 'dialogue' appears showing you the discussion thread.(Technical Details)
You can add to the discussion by typing in a response and clicking the 'Reply' button.
The new discussion entry is immediately visible in the task list.
And of course as a new reply within the Discussion List thread..