Good question. I hadn't really thought that far ahead yet, about the most ideal form for a developer to respond to comments - just that there finally will be a method. I suppose, first, that it depends on how Google implements this. There may be comments allowed on the comments left by users, and then the obvious move is for developers to respond there. Otherwise, I suppose the developer could make a G+ post and share it with just the person who commented, or send the user an email if that's an option.