- Lostpedia: It has been stated by Damon Lindelof and Carlton Cuse on the Official Lost Podcast (February 22nd 2010) that the flash-sideways is NOT an alternative timeline, and that the two timelines are not mutually exclusive.*
To me this means that what we as an audience are witnessing in the story is something known as a 'Temporal Merge'
"Temporal merging is when each action committed in time travel actually overlaps one reality with another. For instance, if a time traveler were to meet his double from another time, the double would merge with the time traveler, making the traveler a part of the time he is visiting. The same would hold true for events. Two events would merge into the nearest event which does not produce a paradox." - Wikipedia
I know people think that a time loop or paradox was created when Flocke told Richard to give the compass to Locke and the events with the compass that followed (preceded actually).
I would consider this valid prior to the Incident, but it seems clear to me that the nuke at the Swan site would have been the catalyst for the temporal merge as evidenced by what is unfolding on the show in both timelines. Of course we will see the conclusion of this temporal merge within the season which I am enjoying watching unfold.