The metagame elements of Journey are one of the concepts that make it unique amongst game systems.
In the realization that there were two extremes in game design - one being a system by which all events are determined numerically or by the dice, with no player input; the other being a system where only player skill, not character skill, matters - we came to the realization that we have to fuse the experiences of both player and character into a cohesive whole. Out of this realization was born the crafting grid for artisans: the concept that the player must do something that mirrors, or somehow represents, what the character is doing.
Each role in Journey has a metagame element. A player can choose to ignore their metagame element entirely. However, if the player chooses to utilize their metagame element, they may receive in-game benefits (or possibly suffer in-game penalties, for some roles, depending on circumstance of the usage of the element).
The warrior's metagame element is the tactical, by which we mean the tactical grid upon which combat occurs.
The benefits of the tactical are rather obvious: it gives the warrior's player the ability to see the combat situation from a bird's-eye perspective, allowing him to better understand positioning, make use of terrain, and exploit tactical advantages such as flanking.
However, there are potential drawbacks. Just as the warrior can exploit the tactical grid, so, too, can his enemies: the PCs are not the only individuals who can enjoy the benefits of flanking or terrain.
The explorer's metagame element is the map. The explorer's player is expected to maintain a map of whatever environment the group is in, allowing them to find their way.
The benefits of the map are, again, rather obvious: it gives the explorer - and the group as a whole - a better view of the terrain. In addition, when keeping a map, the explorer's relevant skills (based upon the sort of environment being mapped) allows him to find things that may otherwise have been missed - shortcuts, disguised traps, or tracks of other creatures.
The lorist's metagame element is metagame knowledge. The lorist is expected to maintain notes and records, and - by virtue of these - acquires knowledge that is not normally considered accessible to denizens of the game-world.
Using this particular element requires a bit more thinking and forethought than the others. It gives the lorist access to information that would not otherwise be accessible; for instance, while everyone may know a dragon breathes flame, the lorist will be able to ascertain game-mechanics aspects of it (such as damage dealt, avoidance TNs, and the like). This enables the group to have a better handle on the threats they face, while also representing the lorist's pursuit of knowledge that goes beyond the bounds of reality.
The lorist is expected to maintain notes and records for the group, particularly game-logs. The LM will then provide more detail than the lorist has kept based upon the lorist's particular skills.
The artisan's metagame element is the crafting grid. The artisan is expected to be able to piece together the various parts that go into crafting items.
The crafting grid is intended to draw the artisan's attention away from the table while it is being used, which is intentional: while the artisan may be present for group discussions while he is crafting, he should be more focused on the work at hand rather than chit-chat. It reinforces the idea that the artisan has a job to do that takes time to perform that cannot be spent while out in the world, and must instead be done in the safety of the forge.
The mediator's metagame element is roleplaying. The mediator's player is expected to be able to engage in roleplaying scenarios with various NPCs encountered in the course of play.
While not everyone may excel at roleplaying, it is expected that the player's actions at least somewhat reflect the character. Dice alone cannot craft a witty rebuttal or scathing insult - these must be provided by the player. Well-crafted words can bring a bonus to the character's rolls, while a bungled speech may impede him.
...the journey of a thousand miles...
...begins beneath your feet...