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Efficiency -- This design is quite efficient. The user can fill in what he wants when he want, and since the final product looks much like the input, there should be no confusion for the user as to what he wants to edit where.
The issue arises when the user wants to create a new resume. Since there is no central store of information, every time the user creates a new resume, he will have to start from scratch.
Safety -- Since any resume can be edited at any time, the design is quite safe. However, people cannot un-share a resume once it has been shared. Also, if a user tries to logout or go home when in the middle of updating a resume, the interface will pop up the "save" dialog automatically so that work is not accidentally lost.