Zimbra's comment service works in applications and status messages to centralize comment creation and reporting as well as make the service available to third-party applications and content via the APIs. The comment service is instrumental in spam comment identification. (Zimbra Community continues to support out-of-the-box plugin features such as the word replacement filter with this service.) HTML is automatically scrubbed out of comments.
Zimbra Community gives you notifications when someone comments on your content or on your own comment. The notifications can be viewed briefly in Live Alerts or in your Notification Queue. You might also receive email notifications of comments, depending on how your Settings > Notifications are configured.
The comment service encourages community participation - inspiring registered users and anonymous users (provided the user has the necessary permissions) to comment on blog posts, media gallery posts, wiki posts, or on status messages.
Community members can view comments on any piece of content they have access to and can comment on previous comment(s). Comments will appear in the Activity Story Stream. This service's APIs can be used with the Rating service to require user comments when they rating content - thus creating content reviews.
Comments are incorporated in the content quality score weighting. This weight affects what content the system displays as high-quality content to members.
As a service, the comment service provides engagement with community-internal content and third-party content with REST APIs, platform APIs, and widget APIs. In each case, the service returns the same kind of comment data.