The producers don't do the promotions; ABC does. And it is Jack's eye from the opening shot of the pilot. All you have to do is freeze frame the image and compare it to this one from the opening shot:

http://images1.wikia.nocookie.net/lostpedia/images/a/af/JackEye.jpg

They are exact except for the pupil dilation.

From what I understand, the promotion department at ABC isn't privvy to what the producers and writers of "Lost" have planned for the final season. Given the secrecy surrounding the show, I doubt that they are in the circle of trust. They're advertising people, after all. Their only job is to get people to continue watching the show.

I respectfully disagree. Lost producers never just show us something for nothing. It's what it represents and is symbolic of - something Lost is famous for doing. Just another one of their little subtleties.

They wouldn't make an advertisement out of nothing; there'd at least be consulting on what to promote. Even if they weren't told any plot details, I'm sure they only showed the eye with the input of the producers.

For the episodes, they are given the clips etc to work with after they are filmed, and put it together from those... but since nothing would have been shot for next season yet, they would have had to have worked along with the producers to properly tease it.

It's simply a commercial for the following season. It takes place after the show has ended and the Bad Robot logo has come up. And no, not everything has meaning. How many times have the previews for the following episode been edited so that you get a completely wrong impression of what will happen? And the producers don't oversee the "enhanced" episodes, so they don't sign off on everything.

I work in marketing, not for ABC but as I said above, there's no way they'd just go through old footage to make a promo for next season. Usually, yes, they are given the episode (or clips from the episode), and make the promos from that which sometimes ends giving the wrong impression, yes, since they only are given clips and don't know the full story (perhaps for fear of spoiler leaks). There's also been times (not sure about this for Lost, but for shows in general), where the clip ends up being dropped due to time constraints. It's an unfortunate part of marketing.

BUT - this case is NOT the same, because they weren't given the next episode, as there is no next episode shot yet. So they would have had to consulted with the producers on what to show, what to film, etc. to tease the final season.

All they show is an eye, which is Jack's eye from the opening shot of the series. There was no additional filming. I just think some people are reading too much into it. It's not Juliet's eye, so it doesn't mean that she's really alive. It doesn't necessarily mean that season 6 will start in the same place as season 1, with a rebooted timeline. It's advertising.