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As an editor, instructor, and collaborator, I would like to be able to make changes in TeX documents that are tracked so that the other person sees what changes were made.
Word has the capacity to track changes with redlining, and I've heard of a custom version of BaKoMa with this feature. I use TeXShop but could be convinced to switch.
marginpar are ways to indicate changes to be made, but I'm hoping to track changes in successive versions of a document.