Yes, you read it correctly, commenting on this site. It is now possible. See the bottom of each page on this site, click this link:

…then, fill out this page:

…click the ‘Send’ button and you have commented on a post. Congrats, use it well, as we all know that:

With great power comes great responsibility.

It will be my pleasure and responsibility to forward your comment to the author of the article you commented on.