I dunno if this particular Jacob theory has been posted, and if it has then I apologize.

So I changed my mind. instead of my connection to the Simpsons, I have another Jacob theory. Jacob is the island. Up to this point we have never seen Jacob. Lostpedia says that the guy that we see as Jacob when Locke is first there is a crew member or whatever. My theory is that the island, or "Jacob", uses the dead to communicate with others. thats why when Locke asked Christian if he was Jacob he said "No but I can speak on his behalf", because he is saying what the island is telling him to say.

When Michael tries to kill himself off the island Tom says "the Island wont let you". but then when Michael freezes the bomb long enough for them to get on the helicopter, Christian Sheppard is on the boat? if he were alive, how the hell would he get to the boat? he would just swim there and avoid all the people and somehow make it to the basement unnoticed? the only way it makes sense is if its the island, showing up in the form of the dead Christian Sheppard to tell Michael that he can die now.

This is also why Locke tells Jack that the island isn't actually an island. the island can think and speak for itself just like a human, hence the human name.

In the Bible, Jacob supposedly has 11 children. so lots of children, the youngest of which is named Benjamin. So Jacobs, or the islands "children" are actually the Hostiles, thats why they all refer to him as their "Leader"

According to an E! Online interview on May 23rd 2007, in response to the question if the role of Jacob had already been cast, Damon Lindelof stated "False; you do see a guy, but... I'm still sticking to my false." well that guy that you see is someone that Jacob is using, possibly an old Dharma guy or something.
I could give other examples but I'm too tired right now. there is actually a Lostpedia theory on this, making me think its not that implausible. what do you think

Yes this is a very good theory....
But  I thing jacob exists or existed and died.....
In the final episode of season 4   while ben was moving the island looked at a spot high an said i hope your happy now jacob....
Thats makes your theory very possible jacob knows everything sees everything hears everything..
But if  jacob was the island whats the need for spies as eithan ang goudwouin(i cant spell that bastard) and how he didnt know about the trap the losties set up for the others(season 3 finale bombs in the tents)

 I  think  the others dont protect themshelves..
they protect the island...
And he doesnt tolerates them he choose them also from the lists.....
He chooses the "good" ones those who deserve to live in this miraculus place and take adfvantage of its healing etc effects,but they have to protect it.....
I think    you can never be sure with lost....

he may wanted ben to fail...
remember richard telling locke ben is wasting our time etc?
Richard seems to be close to the island so  seems to be close to jacob....
Show he probably knew something....
Ben had lost the favour of the island and jacob...he had cancer,he stopped having dreams he just wanted to remain leader and shot john because he was the new "special guy "  in the island....jacob couldnt tolerate those so he managed to make him fail....

AND OFCOURSE IN THE EPISODE THE MAN BEHIND THE CURTAIN WE HAD 2 OR 3 GLANCES OF HM AND HIS EYE...SO WE KNOW HE IS AN EXISTING PERSON.....

Those could be the eyes of anybody

It could have been figuratively speaking. As in someone who looks out for Jacob, therefore making it Jacob's eye.

i didnt think about that DK. good point