As players in the current campaign of Strategic Primer are beginning to tentatively expand beyond a single fortress each, it’s time to explain the central game mechanics that any such expansion involves: messages and information delay.
When you, the player, give an order or other instruction to a worker or unit that isn’t in your headquarters, unlike in other games, the worker or unit doesn’t somehow magically receive the order instantly. Similarly, when a worker or unit sees or does something outside your headquarters, you don’t somehow magically learn of this instantly. Instead, as you’ve seen, you get any results when the worker or unit returns to headquarters—or when they are transmitted as a message.
A message—orders, results, blueprints from an advance, plans for a new fortress, or something else—is passed as quickly as it can be. Late in the game this can indeed be practically instantaneous, as technology can permit the transmission of information at high speed, but at this point the only real possibility at long distances is by the hand of a messenger.
Messengers are workers, allocated to that task by you the player or your deputy. They use the fastest mode of transportation available to them to carry messages (and possibly other supplies) to and from units, fortresses, and other outposts in the field. (And they can even be used to carry routine diplomatic correspondence.) This is far better than having to explicitly specify how each new order is to reach its destination, to say nothing of only giving orders when units are in headquarters and only getting results when they return.
On the other hand, messengers are not a problem-free solution. Their first drawback is that they are as slow as the fastest available transportation, which in the early game is quite slow—finding a unit in the field, delivering an order, and returning can take several turns. (Note, however, that since they aren’t exploring but rather moving so quickly as to barely notice the terrain they’re passing through, they can move somewhat faster than explorers.) Second, they can be intercepted—captured en route, and the messages read—if they pass through hostile territory. And third, they’re labor that can’t be used for anything else.
But on the whole, until players develop the technology to replace them, messengers are a necessary feature of a developing empire.