My team is using Paper for meetings: instead of all working through a meeting points linearly, each of us address different points at the same time, while on a video feed, and write our thoughts directly in the document. This creates a live "minutes" doc of the meeting, instead of having one person take notes.
To make it clearer who has written something we each pick a highlighting colour &, once we've finished formulating our response, we apply that colour (I know you label edits on the side, but it's pretty subtle, and in this mode, we're looking for really obvious). After responding, we tag our response with a comment where we tag anyone who may want to read / respond to what we said (this way the sidebar with comments acts as a notification center: telling us whether and where we need to reply).
It'd be awesome if this highlighting could a) happen automatically an b) be something that could be toggled on / off.