There seems to be very little consistency across most sites when it comes to placing the comment form.
Which do you think is the most usable, above the comments list or below?
Above the list:
Below the list:
I always prefer to think about the use-case I want to encourage, or that is forced by the nature of the site/audience.
If most of your audience will read the content and immediately want to comment, put it on top. If on the other hand you want to encourage people to actually read what others have commented before them and only the respond, it makes more sense to put it on the bottom.
IMO there are activity streams/status casting like Facebook/Twitter's "What's on your mind"/"What’s happening?" where the entries are usually ordered in reverse chronological order to show the most recent items first. The input for this type of entries is put on top. The user enters the text and the entry is places right under it.
Comments on the other hand are in chronological order, the most recent item/reply last. IMO the comment form should be placed after the list of comments, because there where the user writes and where the comment will be displayed.
I find that putting it on the top is often distracting. on the other hand a site with a lot of comments forces a lot of scrolling if the form is on the bottom.
I like @Dan's idea of considering the audience but would add an idea.
If you do put it on the top make sure it is clean and simple so as not to distract from the comments below. If you put it at the bottom put a "click here to add your comment" (or something similar) link that skips to the comment form.
It can be helpful to consider the page's semantic structure, or basically how it would render with the stylesheet disabled.
Does it make sense to prompt the User for comments before they read the post? In most circumstances, I would guess not.
If you're considering the accessibility of the page, then having the comment form above the post might make it difficult for a screenreader user to find the actual content.
r.
How about a collapsible Add Comment link (which unfolds an Add Comment form) at the top, with the full (expanded, uncollapsed) Add Comment form at the bottom?
This way you won't distract the user who wants to read the comments first, and you also provide a way for the determined commenter to do so quickly.
In long entry fields like this, I tend to put input fields where they're going to show up. If my comments list shows comments in order by date, descending. I'll put the Comment box above the others. Otherwise, I put it at the bottom of others.
I almost never duplicate fields though, I'll just put in an anchor at the top that says something like "Add a comment" that takes them down to the form.
If the comments are ordered chronologically, the comment form should be place under the last comment. This will make the "random thoughts from people" a "discussion". + the user goes through the other comments
Agreed with @Ryan up to some extent. And in fact providing comment link next each entry and when the user click that link or icon should open up as modal window.
Reason for putting modal window is that user is in mind-set of entering the comments so he is focused. Even if the main content get shaded does not matter much. That way it is not necessary to go down to the page to fill the comments.
Regards
I'd offer a variation on Ryan's comment. Instead of a collapsible form at the top, I think placing an anchor link to the form is the best option. I wouldn't put two forms on the page as that's just confusing and clutter. I think you want to give users the opportunity to go right to the comment form or to read what others have said first.
My preferred implementation is as follows:
Obviously no one is more interested in comments, so putting it on the bottom would be better.
