To participate in a discussion, you must reply to messages that other participants post.
To reply to a message, follow these steps:
Note: You must have Discussion - Post permission to reply to a message. You get that permission by subscribing to the discussion.
Note: If the discussion owner allows it, you can also reply to a discussion by email. The email address of a discussion is something like this:
<discussion name>@<project name>.<domain>. You can turn off this email option for your subscription at any time through the Subscription Settings page.