No, not that kind of change.
I’m talking about whether the course of time has really been changed on Lost when they detonated a nuke on the Island. In the first episode of this season we are led to believe that things have changed. We see the Losties back on their Oceanic flight but this time it doesn’t crash. Maybe it worked!
But we also see the Losties on the Island after Esau (Smokey) has killed Jacob and nothing has appeared to change. Which one is the real timeline?
The answer, I suspect, is that they are still part of the same timeline and nothing was fundamentally changed by the nuke. Yes, Oceanic landed safely in LA, but I’ll bet that all of the Losties will make their way back to the Island over the next few episodes and the two timelines will merge. You can’t change time.
This seems to be the major dispute between Jacob and Esau. When the two of them were sitting on the beach watching the ship, Esau said that it always ends the same way. Jacob agrees but says that the process is always different and that is progress. We’ll somehow learn that Jacob is right about this. We’ll see that there has been progress even if the ending is the same.
Some evidence for this theory is that Juliet seems to be dangling between the two timelines as she is dying. She talks about going to get coffee and wants to tell Sawyer that it worked. Also, Desmond appears and disappears on the flight. I bet things are changing in the alternate timeline to course-correct already.
Some other questions to ponder: Where is home for Esau (Smokey)? he tells us that he finally wants to go home and I’ll bet that is the Temple from which he has been banished and will now attempt to recapture.
Also, is Jacob inside Sayed? It seems like Jacob gave Hurley the guitar case as an insurance policy. He knew that he could visit Hurley even after he was killed and deliver the message to his followers at the Temple. The message may well have been to use the pool to transfer Jacob into Sayed so that Jacob could help defend the Temple against Esau.
Even though Jacob seems like the good guy and Essau as the bad one, I’ll bet that they are both actually mixed in character. Each has done good and bad things. We will somehow learn that both are correct — fate cannot be changed but there is still room for free will and human progress.
Jay P. Greene's Blog 
I’ve been anxiously awaiting your commentary on the latest Lost episode.
My intuition was that the nuclear explosion was always part of the time line (and explains why it was that people on the island suddenly stopped being able to have babies). Faraday thought the bomb would change everything when in fact, he was putting into motion what had always happened, just like his mom knowing all along that she would ultimately kill her future adult son.
I’m not sure what to make of the other time line. Maybe it’s supposed to serve as a counterfactual to show how pathetic everyone’s life would be without the island and “the progress” it provides. But I think your theory is more on the right track.
My big question is how did Ben end up thinking Esau was Jacob and meeting with him regularly in the cabin without Richard figuring it out? Richard obviously has a past with Esau. And why would Jacob have bodyguards (as Esau refers to them) across the ocean in LA? I’m no expert on personal defense, but if I felt I needed bodyguards, I’d prefer they were in close proximity.
These are great questions, Adam. Are we sure that Ben was really meeting with Esau in the cabin? We know that the dirt circle around the cabin was broken when Ilana and the bodyguards appeared, but how long has it been broekn allowing Smokey to get into the cabin?