The most important capabilities are: any edits must be side by side with the original for fast comparison, editors must be identified, and the text of each version is numbered using autonumbering for each stacked level of headlines, subs, paras and subparas . and bullet points etc.
With the latter it is much faster to locate the text commented upon, using the number. It helps to track any shifts in text order also.
I only know commercial software that does these things (and much more) for this purpose. But I am sure there is an Open Source version of it out there. You can't be me, I'm taken
But this process assumes that one or more members of the approval group have exclusive editing rights. Only commentary is allowed if you don't have edit rights. The document can be locked in different ways.
But comments can be quite long - people often paste whole paras that they've rewritten into comments - and that makes it easier for the editor too - copypaste.
This process is perfect also for visuals and layouts. Pointing a comment at exactly what you are commenting is much easier than explaining in words to what you are referring. You can do this in Photoshop too but the files get so damn big, and people get itchy about interfering physically in the layout without competence. So a pdf is more secure. You can't be me, I'm taken
