Alternate Timeline Explanation by iCarp

A friend and I where at a party a few nights ago for a friends graduation party, and while slightly intoxicated we began to discuss theories on how the show may end. I recently posted a theory a few minutes ago, but this one explains what the Sideways Time Line represents.

First my friend brought up a good point about Desmond. He said that Desmond and the Smoke Monster are closely related, for they have both wanted to leave the island since they first step foot on it. Also it would explain why Desmond can move through time and also why he is not affected by the electromagnetism. Because we believe that Desmond will end up becoming the New Smoke Monster, not out of hate, but to protect the island with the new Jacob, which we believe is Jack.

The new time line is basically not a game between Jack or Desmond, but a new reality for those who have sacrificed their lives for the good of the island. Which would make sense, for it seems all the Losties are coming together because of either Desmond or Jack. And the two of them are bringing the Losties together so that they can remember there past life on the island and life possibly hapily ever after together off the island.