[uf-discuss] Threaded Comments

[Ashley Kyd]

Dear The List,

I'm in the planning stages of writing a piece of software that's going
to depend heavily on microformats. Ideally I'd like to implement a
threaded comment system, which by the looks of it hasn't been discussed
under the comment discussion on the wiki.

I can see issues with a microformat that covers both threaded and
non-threaded comments, however.

Take the following non-markup example of a threaded conversation (as
seen in vBulletin & DeviantArt):

Mary: Hello
  Tom: Hello, Mary!
    Mary: Hi, Tom.
  Betty: Welcome.
Joe: Completely unrelated to the above.

Compare this to the linear version, in use by most software today:

Mary:	Hello
Tom:	Hello, Mary!
Mary:	Hi, Tom.
Betty:	Welcome.
Joe:	Completely unrelated to the above.

The issue comes when you try to create a microformat that encompasses
both styles.

Ideally, a threaded conversation would include nested elements (for
example, lists) to show a relationship.

<ol>
  <li>Mary: Hello
    <ol>
      <li>Tom: Hello, Mary!</li>
    </ol>
  </li>
</ol>

However, a linear discussion would be better suited with just the one
list. 

<ol>
  <li>Mary: Hello</li>
  <li>Tom: Hello, Mary!</li>
</ol>

The problem is that just a single list shows no explicit relationship to
the last comment. So if the microformat was going to include some method
of determining a comment's parent (who the comment is replying to,)
there will have to be two meanings - one for nested elements, and one
for linear elements.

Concise version:

* Threaded comments have a semantic relationship with the last comment.
* Linear comments have an _implied_ relationship with the last comment.
* Any microformat is going to have to have two modes: one threaded, and 
  one not.

Is what I'm saying making sense?

Regards, 
  Ashley Kyd
  Making trouble for everyone.