We’ve come to a solution for the dreaded double post on blog replies. And by we, I mean other people than me within the company, I was just the one lucky enough to implement it.
We created a random “formid” key that gets put in the reply form as a hidden field (which is easy as md5(uniqid("")) in PHP). Then when the form is submitted, we check to see if a reply already exists with that key. If it exists, then it means its a double post.
So voila, all of a sudden you no longer get a double post when someone replies to your blog entry, and then refreshes the window to see if someone else has replied (or some other random reason - who really understands the mind of users).
Got a better solution to this problem? Feel free to tell us how dumb we are.