They've been lurking in the background for the entire series, and last night, Fringe's bald Observers finally stepped into the limelight. Here's what we learned about the mysterious beings who've been spying on the Fringe team.
They can catch bullets. The ability to catch bullets probably comes in handy when you hop around time observing significant (and often violent) moments in history. But August's Superman stunt is just another sign that the Observers aren't human (or if they are, they are extremely altered), and that they can be powerful, even if those powers are rarely used.
They know the future (to some extent). August says that he can see Christine's future, and he knows both what she is about to say before she says it and when the report of the crash will come on TV. And the Observers watching Olivia and her niece comment that it's a shame things are going to be so hard for her. On a side note — are we supposed to automatically assume they're talking about Olivia, or could they be talking about her niece?
They can still be surprised. At least, they're surprised when August interferes with the natural order of things. Are Observers the only ones with free will, or do they observe to see how individuals react to these big, important situations.
Their writing is culled from various civilizations. So it turns out that the Observer language isn't a language at all, but simply words written in various languages from throughout human history (and perhaps other people's histories as well). It's got to be a handy way of communicating exclusively with people who have an encyclopedic knowledge of all languages ever written.
They appear at important moments in history. We actually know this from the promo campaign, but the episode makes it official. Also, the increasing frequency of Observer appearances suggest that the most important event in human history is about to occur.
They eat fancy peppers. We already knew the Observers were fans of the hot stuff, but hot peppers are a handy way to track them. Will the apocalypse be marked by record sales of hot peppers?
They sometimes make mistakes — ones that require "correcting." So, sometimes observing affects the outcome, but we still don't know what mistake prompted September to save Walter and Peter. Did September cause Walter and Peter to fall into the lake all those years ago, or does the Observers' correction require Walter to survive for an entirely different reason? Or did September get attached to Walter and Peter the same way August got attached to Christine and simply convince the other Observers that he was fixing a mistake?
September made some kind of deal with Walter. Walter says he had an "arrangement" with September, presumably so he could keep the alternate universe Peter. Apparently, the other Observers know about this, but we're still left to wonder what the exact nature of this deal is, and whether it relates to Walter's particular relationship with September.
They can feel love. The Observers are apparently also changed by the act of observation. And, now that they're observing the same people for extended periods of time, I'd imagine it's more likely that they'll get attached.
They can be killed. But what does it take to kill an Observer who doesn't want to die?
Being responsible for the death of an Observer makes you "important." August may be more significant than Christine in this respect, but it implies that the violent death of an Observer is extremely rare — a monumental event in history.
Any other Observer observations?