The sixth characteristic - what Traveller5 calls C6 - varies in its
interpretation, but in all cases seems to be pretty fuzzy in its
definition, unclear as to what it represents "in-universe", and not
generally used in play:

In the Clement Sector setting, it's called Social Status, and is nominally
used as a proxy for lifestyle spending, which is ostensibly tied to wealth.

In the standard Third Imperium setting, it varies by race:

For humans and Aslan, it's called Social Status, and seems to be a proxy
for one's nominal rank in the aristocracy - even if a character is not
considered to be part of the aristocracy. There's some use of it to
detemine how NPCs - often random encounters who have little impact other
than being an obstruction to getting some small amount of information -
will react to the player-character, but it's never really important enough
to derail - or force - an adventure or scene.

For Vargr, it's called Charisma, and ostensibly represents how well the
character can influence others to achieve his/her own aims. It's used very
much like Social Status is for human characters, including its lack of
importance.

For Hivers, it's called Curiosity, and can directly influence the
probability of a Hiver 'having adventures' - basically, a Hiver's Curiosity
can be enough to occasionally override his innate racial good sense about
avoiding personal danger - but Hivers are probably both the most alien and
nearly least-played of the major races (the K'kree might be less-played).

For Droyne, it represents Caste, and is a limitation on what careers may be
entered, and therefore what skills might be accumulated. Droyne aren't much
played, but I don't see how Caste might be a factor in play.

For K'kree, it's called Caste as well, but functions more like Social
Status among Humans but only within the K'kree's specific social class
(Noble, Well-born, Bodyguard, Servant, Female) - between social classes,
it's meaningless; only the relative ranking of the social classes (as
given) matters - a low-caste Bodyguard outranks a high-caste Servant. I'm
not aware of any actual use of K'kree player-characters, so I have no
information of how it actually functions in play. (I suspect that the
general position on K'kree - apart from black humor about barbeque - is
that they're in practice unplayable due to complexity.)

In any case, it doesn't tend to be considered important, and in
character-generation systems that allow some level of customizing the basic
characteristics, C6 seems to almost invariably get classed as the 'dump
stat'.

What I'd like to see developing from this post is some ideas:

1. How can C6 be better-used and more important in play?
2. What *should it mean in-univere?
3. Should it be tossed out, and replaced by something else (and what)?

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