[Mark]

This is coming from another post of mine, where I would find it extremely useful to limit a user to only one top-level post per user per page.

Reasoning - I have a site where people can leave a review of an item, and I don't want them to be able to leave more than one review. I'm happy for them to reply to other top-level posts. The way I envision this feature is that if they haven't commented on the page, they can. Once they have commented though, unless they're replying to someone else, they get a popup like "You have already commented/reviewed on this" 

I've worked through a few hacky solutions where I remove the form through javascript - but this prevents replying to a post, and I have also looked into deleting multiple posts by the same user for the same page from the database... but this isn't ideal. I'd rather have a prevention than an after-the-fact fix.

[Steven]

Hi Mark, thanks for this suggestion, I think it would be a good feature.

In the latest version there's the quick reply feature which shows a small form below the comment the user is replying to. So the best solution might be to hide the main form if the user has already posted a comment on the page, (using JavaScript would be okay), and allow the quick reply feature. There's a link on the quick reply form which says something like "Switch to full reply" but that link could be easily hidden with JavaScript.