I think i have figured alot about jacobs cabin. Some if it definatlly can be proven, and some of it is in my mind common sense. Okay to the point.
First let me say that i am a believer that Jacob had a hand in guiding Ben to do what MIB wanted Ben to do, Kill Jacob. This is part of Jacobs plan to end whatever Lost is about.
Jacobs cabin is just that, JACOBS CABIN. Did he live there? No he lived in the statue.
We know that Richard did speak to Jacob, Ben did not. Richard recieved "all those slips of paper, all those lists" from Jacob and he delivered them to Ben.
I think Jacob started to use this cabin after the purge, which just so happens to be close to the time where Ben took over leadership of the others from Widmore. The cabin was built by Horace for his Lady and i imagine for baby ethan as well but since Horace died in the Purge, Jacob decided to use it. He surronded it with ash so that the MIB could not use it to fool the Others.
I think Jacob used this cabin to deliver his lists to Richard. The cabin has been seen to move, like Hurley saw. Maybe this was better for it to move to Richard as he treks the island, rather then Richard having to walk all the way to the Statue every time a list or order was ready. (Sidenote) When Ilana and co. got to the cabin her words were "some one else has been USING it." which to me implies that Jacob never lived there just used it to talk to people he needed to talk to. I think when Jacob visited Ilana at the hospital she was told the cabin is where she can find him, although we know they were to late because, well jacob died.
Jacob using the cabin when Ben finally comes into power also helped to manipulate Ben which would explain why Richard didnt tell Ben where Jacob really lives. I think this was Jacobs guiding hand, manipulating Ben into thinking that he was not worthy enough to see Jacob(i also think Widmore spoke to Jacob like Richard did, which Ben knew and heightened his jealousy and his feeling of neglect from Jacob) And just in case Ben decides to ignore Richard and go see Jacob, it doesnt matter because Jacob doesnt live there.
We also have to remember in "The Incident" and in "LA X" how much Richard firmly believed: 1. Only the Leader can request an audience with Jacob. 2. There can only be one leader at a time. 3.No one can see Jacob unless Jacob invites them to.
So why is it that when FLOCKE was going to bring BEN with him to see Jacob, Richard was pissed. Yet when BEN was going to bring LOCKE with him to see Jacob, Richard didnt really care, just blending in with the rest of the others in their awe. Why? Because he knew Jacob did not live there, therefor Richard just decided to let Ben think what he wants. Which plays into Jacobs manipulation of Ben. Yet when they were going into the statue, he freaked because thats where Jacob really was.
When John and Ben go to the cabin, we see the ash circle is in tact. So, if we use what we know, the ash circle was broken by Hurley or Claire. IMO Jacob wanted to talk to Hurley right then and there and the fact that Hurley can see dead people leads me to believe that Christian works with Jacob. But when Hurley got spooked and ran maybe he inadvertently broke the ash circle.
Now if Hurley broke the circle, he did this after he was scared by Christian (btw this is the last time we see Christian in his Blue Suit.) and the Eye in the cabin, which i think belonged to Jacob. Jacob was in there then to talk to Hurley. After Hurley ran from the cabin, and broke the circle, MIB was able to use the cabin.
I dont know enough to comment on Claire and her involvement in Jacobs Cabin but maybe she is another one of MIBs pawns. She wasnt important enough to be touched by Jacob, Yet there is something intriguing about the night she left baby Aaron and joined her dad. First thing was that Miles could see Christian. Miles cant see dead people which means THAT Christian wasnt Ghost Christian, like we have seen all the way up until the point where Hurley breaks the ash circle. Second is what Christian was wearing. Not his normal Blue suit, but some Others looking dress shirt. I think this marks the first time MIB has shown up as Christian.What if Cristians body was inside the cabin or atleast the ash circle, which protected it from being used by MIB. Since Hurley broke the ash circle, MIB got in and was able to use the body like he did with Locke. THIS Christian is the one that manipulated Locke to move the island and eventually die.
If Smokey is trying to go home, and if home is off the island than i assume he cant appear to Jack off island as Christian. Which means that Christian was the real Ghost Christian. Yet when the freighter was close to the island, Christian appeared in his Other shirt to Michael.
The Christian that met Sun and Frank was also the smoke monster because A: The Monsters trademark sounds were heard on the dock and B: he was wearing the other shirt (lol trademark Other Shirt). He did this for the same reason he showed up as alex
to ben....manipulation. IDK why MIB needs Sun (doubt he needs frank) but he did say that he could reunite her and jin. He also said she has a long journey ahead of her so maybe we havnt seen what MIB wants with her yet.
So to make a long theory short: Jacob used the cabin to commune with Richard while setting up Ben to feel worthless. He used it up until the point when Hurley broke the ash. After that is when MIB used the cabin to his own end which included using Christian to manipulate John.
PS> Just because MIB started using the cabin doesnt mean Jacob didnt go back to it. I think after He figured out MIBs plan (loophole) he changed his plan, used his own knife to cut out a piece of his tapestry (the statue piece) and pinned it in the cabin with his own knife as a signal to Ilana as to where to go next.