So there's a big debate here on Lostpedia. Is it whatever happened happened or can you change things? Fate/Freewill? etcetc. Here's my idea that includes both!!!
Ben turns the FDW, and...bloop! Unfortunately for all you WHHers this is where i think we get a RESET!!!
Then our friends on the island start experiencing these flashes where they get jumped into different times. And for the WHHers: these KEY KEY times they flash to are events that MUST and DO take place. These are events where whatever happened happened. Let us list them (and i dont remember them all, so please help me!!):
We have (in no particular order)...
1]1950s - Bury the Bomb! Frogurt get's flamed!
2]Post Ajira - In a boat (shots are fired), old beach camp is in disarray.
3]Danielle and co. arrive (and find Jin!)
4]Aaron is born, Locke pours his soul out at the Hatch.
5]Daniel tells Desmond to find his mother.
6]Yemi's Plane crashes, Locke is shot by Ethan.
7]Post Ajira - Richard mends Locke's gunshot wound. FLocke enables the Loophole (which i think is something with the compass btw).
8]VERY brief flash (just to really make sure Charlotte is gonna die!)
9]Statue is visible from where the well had been (but wasnt built yet). Maybe the event with Jacob/MIB watching the boat (Black Rock?) arrive (naaaaa its gotta be wayyyyyyyy earlier than that)?
10]It stops in 1974 (Locke turns the FDW), we join Dharma.
There may be more I forgot about, but I do think that there all seperate flashes, yeah? (I wanna add that one of those brief ones is when Henry Gale [balloon boy] arrives -- mostly joking)
So these flahes are events now that are WHH (and I think are IMPORTANT EVENTS [for example birth or death]). These are the ONLY events that are WHH, and actually im iffy on #5 because I would like to think Daniel changed something by talking to Desmond (I dont think Desmond had buried this memory, I think it didnt exist until Daniel make it).
Everything between the flashes, is yet unwritten (even if weve seen in or have heard reference to it). Whatever gets written in these gaps though MUST directly lead to the events we see in the flashes, however.
So for example; Aaron will always be born on the island, with Kate's help, the day Locke pounds on the hatch. He may not arrive via 815, but this event WILL take place.
Im sure the universe has a natural tendency, and without coercion, events within those gaps would take place as we witnessed in seasons 1-4 (or 1-5 i suppose...). But with coercion, slight modifications may be made, as long as it enables those flashes we saw to come about.
And I just want to plug one last thing -- KEEP YOUR EYES ON THE COMPASS!