I deeply appreciate Colin's posts about previous submissions and routinely upvote them. What I like about them, as someone who has been on Hacker News 1838 days now, is that they answer the "Haven't I seen this before?" question that often pops into my mind when I see a recurrently posted story. Because this site's name is Hacker News, after all, I expect to see new stories submitted here, so when an old story is submitted it's helpful to know where the previous discussion is.