Poses are actually more important in comics than any other visual media, as the image never changes.  Every drawing you place down has to be as efficient as possible at conveying your intentions; you can’t fall back on motion to get your point across.

Body language does more than convey an emotion or an action, though, they tell us about the characters.  How a character stands or emotes can tell us a lot more than what they’re actually saying, or what back story we’ve been given about them.  If I’m told a character is resentful or slow to open up to people, that’s fine, but that information can be implied (or at least augmented) more viscerally through posing.  If this character’s body language goes more relaxed around well-known friends to stiff or slouching when around new people, for example, we unconsciously begin to associate the correct traits with the character.  

In short, how a character moves is just as important as how they are designed.

I’ll use some examples from my own comic, as the characterization in Dresden Codak isn’t overly complex.

Dmitri Tokamak’s body language is fairly straightforward. He’s reserved in both demeanor and physical motion. Partly due to his large stature, his physical gestures are subdued unless he’s compelled to actually smack someone. 

His postures only start to relax when he’s pulling one over on someone or poking fun at Kim.

 Alina Tokamak is Dmitri’s antithesis. Her body language is much more physically active, partly due to her small size, but also because she is more open with her enthusiasm and interests.  She frequently makes physical contact with people, and only really calms down when she has no intellectual grasp of a situation.

She is extremely active around Kim, whom she knows will put up with her behavior without question.

Kim, being the protagonist, is the most developed character in Dresden Codak, and as one would expect she has a larger range of posing behaviors depending on the context of the situation.  She is pensive most of the time, lost in her own thoughts, cripplingly shy, and is very submissive when dealing with new social dynamics.

When caught off guard, she shrinks. The above panel illustrates the difference in attitudes between Kim and the stranger.  He is comfortable in the environment; his angles and arches are fairly straight.  Kim, on the other hand, is coiled, her bubble penetrated.  In reality the stranger isn’t being intrusive at all and isn’t invading her personal space (if he were, I would have stretched his pose further, and had him crossing the invisible dividing line between the two characters).  This panel describes Kimiko’s behavior: an overreaction to a mundane interaction.

When Kim has an idea, it has to come out. She’s known to go on without any regardes to others’ understanding of what she’s saying, and while this is partly conveyed in dialogue, her physical behavior augments the theme.  Her eyes widen, her posture shifts to a sharp angle (toward whomever she has decided to talk to) and she goes off.  This behavior of Kim’s is the only one that isn’t context-specific.  She will do this regardless of whether she is in the presence of a stranger.

Her posture shifts dramatically when she is in her element (generally in exploration or in her laboratory).  Her mind is hard at work, and her confidence shoots up as she is occupied with unraveling a mystery.  Her slouch disappears and her physical gestures more clear.

Compare Kim’s reaction at first to the Sleepwalkers:

To when she begins to explore their world by herself:

Individuals have unique ways of speaking, but their bodies exhibit “accents” as well.  A tilt of the head, the placement of hands, and the direction of the spine can show the reader a lot more than telling them alone.