The Flash-sideways are moments in the real universe by Lester Burnham

Obviously everyone has been wondering what the alternate universe/world/timeline is and I've decided to come up with my own theory. It spawned from being curious about why Illana carries a bag of Jacob's ash with her all around. As we saw this week, she used it to have Miles let her know exactly how he died. She had efficient time to have asked Miles this already and if that was the main purpose of carrying it, not only would she have asked him right away, she would have gotten rid of the bag afterwards, however, she finds it important to keep with her at all times. Why? because she is on Jacob's side and knows that MIB would kill her just as he did the rest of her crew under the statue. We have seen Bram throw ash around himself for protection and we also know ash was used to keep MIB away from places such as the cabin.

This is where my theory comes in. I, just as many of you I'm sure, do not think just any ash will have this kind of effect. I think the ash that is used is that of the bodies of all the other "Jacobs" that have existed in the island's history. We know that MIB is unable to harm or cause any damage directly to Jacob himself. The events that happen on the island are monumental necessary actions needed to preserve the REAL universe, which I think is the flash-sideways. Every certain number of years, certain people have the important task of maintaining time. A "Jacob" is appointed to effect people's lives at times where a threat is growing for the world's safety and his touch obviously brings them to the island as a recruiter tool to do so. This splits off and creates an alternate universe that is specifically designed to ensure the continuance of the original one. MIB wants to be released from everything he has ever known and is driven to destroy the universe/time. Our Losties! were brought there because time would have looped forever had they not originally crashed into the island in order to go back in time to make sure that the machine that brought them there was never built so they could "save the world" right at the hatch just like Desmond said they were doing. They would exist in the 70's only to set themselves up to crash there 30 years later only to go back again. "What's happening is always what happened." Now our heroes have saved the world and time will continue on, but the show is all about finding the new "Jacob" just as I'm sure this scenario (in one form or another) has played out since human existence and always will.