So far, the backstories have been for Jack, Sun & Jin, Sawyer, Locke, and Eko. I remembered that a lot of fans were very dissatisfied with the first third of the season because so much time was given over to the three captives staying with "The Others." But on rewatching this, there has been plenty of stuff apart from "The Others." And, we needed to know as much about their set-up as we could so that the latter episodes in the season would have greater resonance.