The party comes across a nice hermit in the woods. He gives them food and lodging for the night. They awaken to his terrified screams. "East! It's east! Stop it! It'll kill us all!" The poor horror-stricken hermit dies thrashing in agony, one boney arm outstretched, his finger pointing to the east.
A certain patch of forest is well known for causing anyone who ventures into it to suddenly go blind. Once they leave the area their vision returns. Rumors of treasure hidden within.
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.