A lot of players right now don't even have "motives". Even the two baddie teams (or the baddie team and the independent team?) don't really have a clear goal... the red team has to eliminate detectives, but they all want to appear to the thread as detectives, so it's very easy for a red team member to go hard with a case against another red, thinking they're getting a detective, wanting the thread to think they're going after a baddie, and really having no idea what the reality actually is.
For all we know, the best case-makers are all red, and they will be awesomely convincing and get us to lynch their teammates, while the Civvies sit back and lay low while it happens. It could be! That's so backwards! Maybe you want to accuse me of some sort of manipulation by suggesting that, but even if I were red, how would I know?
I just looked back at the roles to see if I missed anything and another thing that is a major part of the game is the receiving of Death Notes... a major part of the game that we cannot use for anything because we don't know what the deal is, how they get received, when this happens, if there's an element of chance or skill to get them...
So if people are mostly individuals, their biggest motivation is going to be personal survival. A Detective, trying to survive long enough to somehow catch a Kira, will want to be really careful about what he says, so as not to attract too much suspicion... unless he wants to try and be extra-outspoken, to both attract suspicion AND seem like a useful player to have around. Wait, no, I just described how a baddie would probably want to play. See?
After talking this out with myself, I find myself on boo's side of lynching low-posters... at least until some game elements coalesce into something more tangible. Hoping that will happen. Also, I tend to agree with his other points about low posters. I don't think it's an acceptable tactic to specifically not post so as to make it to a later part of the game, knowing that people won't vote for them.
Then again, I'm pretty sure I'M a low poster in this game, so there's that as well.

I don't want to be lynched.
If you read all my thoughts here, and you have a different opinion on how to get a more solid handle on this game, then I'm all ears. There must be something more we can use, and it's not currently what we'd use in a regular Mafia game, where baddies have BTSC.