if you have one little tiny comment on a post you're sharing, you don't have to make it a whole-ass reply that sticks with the original when someone else shares it. you can just add a tag, the way they do on tumblr, and it will only show up for people who see your first share.
it's tiny and unobtrusive. less like a "quote tweet" and more like if you could add a little sticky note to a retweet
