I dont know if anyone else noticed this, but during Olivia's second vision--the burning city-- you can see scrawled on the wall of a building in red graffiti "HE IS HERE!"
I dont know if this is implying the Observer...certainly it has in the past, but who knows...maybe it is someone else. If it does mean the Observer, does that mean he is in some way responsible for the events that are taking place?
I'm not sure how much this relates to the Observer, because that is all he is in my opinion, an observer.
It might be just a religious thing meaning the apocalypse. I've also been thinking about what Walter said to Astrid in the end of episode 1.14. Where he said "It doesn't kill you, it does something unthinkable"... It could give the person unknown abilities, which has caused all the destruction in Olivia's Visions.
Walter Bishop: "it always comes back to the duck"
I think the text could have something to do with the Observer.
Consider these images:
This is from an early poster of Olivia lying in the tank. This one:
This is from the intro and it's using a similar wording.
Blog: Gameboy Genius
Code:04:02 <+tl> they say "your health is our business" =-x sounds like they're going to steal my kidney =-x