When multiple people are working within the same estimate it would be helpful to tag another user to have them look at something. This would also require a way to notify users of active tags at the Workspace level.

I like this.
It can also extend to a worker's task list.
IE: tag workers, with questions, or even direction.
Bob, do a takeoff on wall removal.
Fred, find details for concrete
Kevin, do we have room in this area for Taco Tuesday?
It can extend more to a chat log for a certain question. (Task list turns into a chat subfunction)
Fred: Bob, do we have enough room for a lift
Bob: yes, at so and so size.
Fred: noted, whats the weight limit of the slab?
Bob: your mom