This game was originally a world-building activity located here: http://wiki.trevismartin.org/pmwiki.php/WorthOneThousandWords/HomePage
This specific version extends W1KW to make it into a full-fledged RPG called Caravan. The game is set in a fantasy world of the players' design that evolves as the titular caravan the characters are travelling with moves about the world.
Characters in Caravan belong to a merchant caravan that voyages between cities and trading posts across the known world. Players should come up with concepts for their characters that make sense as either some sort of member of the caravan, or somebody travelling with the caravan temporarily. Note that if the concept seems short-term in terms of how much time they might spend with the caravan, that the character may not be in the game long. This may actually make sense if the player wants to have a short-term character. And that said, even a short-term character concept can become long-term through the course of play.
Typical longer term characters include merchants that work for the caravan, traders travelling with the caravan selling their wares independently, assistants to these sorts, guardsmen hired to protect the caravan, drovers responsible for the animals involved, and even the masters of the caravan itself.
Players should select three terms that describe the character well, and really cover the entire concept for the character.