Well, a big mystery right now is who is in the cabin? Was it really Jacob, and if so how is this possible. Well I had a theory:
What if Jacob was imprisoned in the cabin by Esau or Widmore or whoever put him there, but when the time shifts started, Jacob began to shift along with the rest of the losties all the way to before the cabin was built, thus freeing him, and allowing him to be in two places at once, i.e. in the cabin, and in the statue where he normally resides. And even further more, he could use this freedom to track down the cabin and break the dust surronding it to free himself.
I know it's pretty farfetched, and unlikley, but I still thought it was cool.
In the S5 finale Illana leads me to believe that Jacob was indeed inside the cabin at one point, and the bit of his tapestry atests to this.