"Drinks or info chummer, both cost. One costs cred and the other costs favors. Too much of the former will give you a killer hangover, and too much of the latter might just kill you altogether."
A bartender contact/info broker for the Shadowrun rpg setting, can be easily adapted to any cyberpunk or other high tech campaign.
The size and number of knots in hair, tied around neck, or hanging from belt could signify family, importance, worship, guild affiliations. Being able to translate the meaning of the size and placement of knots can give you a a large understanding of who somebody is.
May be used in a more barbaric society. Where in cities peoples clothes and crests show who they are, barbarians have no need for this so use knots.