The Observer popped up once again in “Jacksonville,” this time crossing in front of a firetruck as Olivia and the team arrive at the scene early on in the episode. Don’t you think it’s about time they noticed the Observer was present during every case they solve? I’m ready for Olivia or someone to finally see him out of the corner of their eye and stop and speak to him. You know, ask him exactly what’s going on.
You can see the Observer in the lower left corner of this image. 
Hopefully once the series resumes in April, we’ll see a little bit more of him. I have a theory on how we’ll see him in “Peter” that I’ll post later.
About the Author:
Sam McPherson began writing for Walter's Lab in August 2009. He also writes for the sites TVOvermind, MovieOvermind and SpoilerTV, in addition to being an administrator on Lostpedia since March 2009. Sam's favorite shows are Lost, Fringe, Doctor Who, Flight of the Conchords, FlashForward, True Blood, and Monty Python's Flying Circus. Follow him on Twitter (@mcphersonator) or send him an email (sammcpherson@tvovermind.com).
Sam McPherson began writing for Walter's Lab in August 2009. He also writes for the sites TVOvermind, MovieOvermind and SpoilerTV, in addition to being an administrator on Lostpedia since March 2009. Sam's favorite shows are Lost, Fringe, Doctor Who, Flight of the Conchords, FlashForward, True Blood, and Monty Python's Flying Circus. Follow him on Twitter (@mcphersonator) or send him an email (sammcpherson@tvovermind.com).
[...] The Observer popped up once again in “Jacksonville,” this time crossing in front of a firetruck as Olivia and the team arrive at the scene early on in the episode. Don’t you think it’s about time they noticed the Observer was present during every case they solve? I’m ready for Olivia or someone to finally see him out of the corner of their eye and stop and speak to him. You know, ask him exactly what’s going on. See larger image. [...]
err, i always thought they only wear black hat o_o