Hi,

I have been co-authoring an org-mode file with a co-worker, and we
started to put comments in org-blocks with the following format

#+begin_comment ems example comment
body of the comment
- a list inside
- of the comment
#+end_comment

I made the following additions to org-exp.el (patch attached) which
allows the optional exportation of comment blocks through the use of a
`block-comments' option line in the file header.

#+OPTIONS:   comment-blocks:t

Currently it only exports to html, and it styles the blocks using css
(added to the org default html css styles).  It also adds id's to the
comment divs which include the authors name, so it's possible to style
the comments by their author (for example different colors by author).
I used something like the following to style our comments (our initials
are wrg and ems).  I'm certainly no css expert, so I'm sure it's
possible to get much nicer looking comment blocks.

,----[comment-style.css]
| div#org-comment-wrg {
|   background: #cdecf8;
|   border: solid 1px #09abe7;
|   padding: 0.5em;
| }
| 
| div#org-comment-ems {
|   background: #d1fbaf;
|   border: solid 1px #78ed19;
|   padding: 0.5em;
| }
`----

Here's the patch to org-exp.el.  I'd love to hear any
ideas/issues/feedback.

Cheers -- Eric