You are right about add-ons.I hate them.What about a link-shortening service like [Suspicious link removed],but with a built-in comment box.The users will have to convert their original URL into a shortened URL and when someone clicks on the shortened URL a comment box would pop up.I think that there was a free online service like this one,but i forgot the name of the website.
Good luck with your project,OP.
That is a really interesting idea. Something to think about down the line, and thanks for the kind words.
add tab FAQ
Good point, will add this week. I tipped your post, please let me know if you have any issues.