I thought it was quite a good episode and confirmed several of my speculations, including that Jacob and MIB were brothers and that the Alison Janney character was their mother (albeit not their biological mother). It made me think of the "he must not be raised by another" warning given to Claire in season 1 and also somewhat confirmed my belief that the inability of women to give birth on the island was connected to this mythology.
I liked the tie-in to Adam and Eve in the cave and the flash to Jack and Kate's finding them. I'm wondering about a tie-in between Jacob and MIB always calling each other, "Brother," and Desmond's calling everyone, "Brother." I'm still convinced that Desmond is very important to the story. I also felt the tie-in between Mom killing off the colony survivers and Ben killing the Dharma colony as a boy. These were very similar looking scenes.
In any case, it was very clear that the basic story was in place from the beginning.