Not sure what the wfw:comment or wfw:commentRss elements are for? Imagine you’re reading my blog in desktop aggregator and you want to post a comment to my blog. The aggregator has no way of knowing where your comments should be HTTP posted too, so you have to open up another tab in Firefox and go to my blog to enter a comment. wfw:comment is an element that provides the HTTP post endpoint in the feed so that aggregators and widget developers can comment inline, just like this. wfw:commentRss is an element that provides you (or your favorite aggregator) with a link to the comments for the post you’re currently viewing.