As changes are made, users will want to comment or add notes to document changes which don't necessarily belong inside the document.
In Simul; comments can be added to document revisions or the individual changes highlighted.
You will find a conversation panel at the top of each version of a document, by default (if no-one has commented) it looks like this:
You can expand the conversation and leave a comment, by typing in the box similar to below and pressing post:
All users with access to the document can now see your comment and will receive an email of a copy:
You can also comment on a specific change to add more context, just select the comment icon at the bottom of the appropriate snippet:
Type you comment and press "Post":
All members of the document can now view your comment and will receive an email of a copy.