How do I add the ability of comments in a Salesforce.com (SFDC) knowledge base articles? Is SFDC providing us any standard stuff for this?
Unfortunately, no. And there isn't any way to add a field like it. A workaround would be to create a custom object that would serve as your comments and it would have a lookup relationship to the knowledge object. That way you would see a related list of 'comments' in the page layout, but unfortunately knowledge isn't an available object for lookups (I tested it just now).
About all we can do is ask for it in a future release on the force.com ideas site.