In the most recent episode, John Locke announces that he's leaving the island (with others). Is he going to Los Angeles to meet up with our never-became-castaways?
Season 2 or 3:
When Jack divorces his wife Sara, they meet at her lawyer's office. Jack says: what's his name? You can have the cars, the house, everything, what's his name? Sara refuses, Jack storms out.
Jack then starts going through her cell phone records to find the name.
Theory: the other man was Jacob! Evil S.O.B.
We still don't know how Jack got his elaborate, mysteriously smbolic tatoo. When/where? Does the 'alternate universe' Jack have the tatoo? Probably not.
Planet of the Apes? Remember when Sawyer, Jack & Kate are first captured by the others? Carl helps Sawyer escape and Juliet promptly shoots a dart into him. The 60 second scene contains very similar music to Planet of the Apes when Charlton Heston is running through the corn field being captured.