Currently there is no general commenting feature, only the blog has that at the moment. I do have plans to make an option for content rating and threaded discussion (for comments) for the main Html Content feature. I don't have an estimate on when that will be implemented hopefully in the next few months.
You could put a forum on the same page but that might be overkill. Another option (for immediate use) is to link to google groups, like Miguel did for his blog