In a game like _2300 AD_ where there is no faster-than-light communication, one might wonder how news travels from one world to the next. Like in the 1700-1800s, it moves at the speed of the fastest ship available to carry it.
"X-boats" (XBs; very fast Communications ships) and "Courier Missiles" (CMs; like the French Merimee in Ships of the French Arm) run up and down the arms, tight-beaming compressed & coded squirt transmissions to their colonies, outposts, stations, and other paying customers. Most X-boats are run by nations, at taxpayer expense. Really important stuff is sent via manned X-boat. More general stuff is sent via CM. Interstellar news, "Magazines" and other subscription services, Holovid entertainment, and electronic mail all arrive this way, and are beamed to the news organizations, magazine offices, or networks.
When an XB arrives in-system, it squirts any traffic intended for other systems in the direction it was headed to a waiting XB which then continues the trip, Pony Express style. The original XB then continues in-system, and begins squirting data as it discharges its stutterwarp. CMs simply enter the system and follow their programming, which usually has them squirt their data and go to some rendevous point to await human maintenance for discharge and refueling. Other CMs are waiting to pick up the transmissions and continue the journey.
After having advanced up an Arm/Finger, an XB or CM will usually have received data for the Down-Arm or Finger world "below" its current position. After discharge, it could turn around and head back the way it came. Thus, an XB crew may work the Sol to Nyotekundu run, then reverse it. Since it takes 40 hours to discharge, however, CMs will usually not work this way, and XBs will usually work in teams to prevent this two-day wait in return messaging.
When one XB (1) comes in-system with data from (say) Up-Arm, it will pass its counterpart headed Down-Arm (2). Another XB (3) is also headed Up-Arm at the same time. Our original XB (1) squirt-transmits to (3) and continues in-system, passing along messages to any outer planets on its way to its discharge and refueling point. For the next two days it sits "on station" where it can (if needed) receive and pass along transmissions to other XBs, but usually four more ships (4-7) will be sitting by, waiting to go both Up and Down the Arm during the first XB's discharge. When its two days are up, the XB may return Down-Arm the way it came, or continue Up-Arm, assisted in the opposite direction by one of the other six ships returning after its own two days of discharging (2 or 3). Thus, you can see that it takes three X-boats to cover only one system for daily mail, per "exit" from the system. This is the reason that Courier Missiles are so popular, even with the military. They are much cheaper, and there's no crew to be paid (and no life support)! Of course, you can get by with fewer ships/missiles if you run mail less often, cooperate with other nations, etc.
Note here that only off-planet traffic ever jumps through these hoops. Strictly planetary transmissions need not be involved with either XBs or CMs. Each system has its own code (such as "sol" for Earth's solar system, or "bcv" for Beta Canum Venaticorum). Note here that worlds are designated by system name followed by a dash and a number. Thus Aurore would be Eta_Bootis-2c. Mercury would be Sol-1. Systems with spaces in their names have them replaced with underlines (_), so DM+27 28217 becomes "DM+27_28217". Spacestations such as L-5 and Station Arcture have their own "domains". Also note that, like 20th Century UseNet postings, the sender may specify a message for only "Local" propagation, "World-Wide", or "System", "American/Chinese/French Arm", "Core" any combination of arms, or "All".
Ships pick up their mail at port. As the XBs & CMs pass up and down the arms, they can carry messages for (say) "Scout@Phoenix.Ship.nom" instead of "jmclure@bcvlink.net.bcv-4". Such X-mails are left at all mail ports along the way, and are deleted once the ship catches up to them (deletion notice propagates from there, so if your ship exceeds the speed of the X-boats, you may get the same X-mail multiple times).
Most Courier ships will make fair X-boats, although you'll want more Communications workstations installed. While one Comm. station can transmit to many different targets, one at a time, X-boats usually are equipped with more than one, in order to speed things up. Many Corps will want their own X-boats for private Corporate data, (especially Trilon, since Kie-Yuma would otherwise rarely get news), and most national colonies will run separate X-boats or CMs...
Outpost worlds, mining colonies, remote scientific installations, and other worlds not on an Intercolonial route will not receive regular transmissions of anything. They will get X-mail and entertainment programming only when an X-boat or Courier Missile is sent their way (almost never), or (more likely) when they get a supply ship. Since most supply ships are not X-boats, however, they may not be able to carry much communications or entertainment programming. Tramp Freighters or Exploration/Survey vessels can earn a few extra Livre by carrying comm/ent. traffic to lonely miners and scientists in less-frequented systems. Like the arrival of a sailing vessel in the 1700, Ships Crews may find themselves very popular in ports of call, as they are (nearly) the only news from home the locals may get for months!
Lt. Col. Du'Frey, on the military base at the top of BCV's Beanstalk, decides he needs to get an urgent message to Scout, one of his Troubleshooters aboard the starship Phoenix, somewhere in the French Arm. He codes and compresses it, and (the daily X-boats already being gone) dispatches it via a set of Courier Vessels headed to Crater, Sans Soucci (DM+36 2219), and Kimanjano. The mail for "Scout@Phoenix.Ship.nom" from "LCGDF@BS.mil.net.bcv-4" heads off in three directions. Near the end of the first day, the ships (with movement 6) arrive in their target systems, and leave copies of the compressed, coded message at the starports there. Meanwhile, the X-boats also get copies and will continue carrying it. Since there's no telling where in the Arm the Phoenix is, the one heading back to BCV-4 will also get a copy, and leave it at BCV's starport.
The Phoenix, meanwhile, has been headed Up-Arm, towards Earth. The X-boat from Kimanjano will catch up with it at Queen Alice's Star, where the Phoenix is discharging. Scout will now get his X-mail or Holovid recording, and may answer it, or head back. Assuming the Phoenix had just finished discharging and had a movement rate of 6 or greater, he could immediately head back to Kimanjano, beating the X-boat carrying the notice that he had received this message, and that it could be deleted from the starports' message bases. Arriving at Kimanjano starport, he could then get the message a second time. If he then caught a second fast ship to BCV-4, he could get it a third time upon arriving at BCV-4's starport. If he stayed with the Phoenix, however, the X-boat from Queen Alice's Star coming along behind him with the deletion notice would pass it to the XB leaving Kimanjano for BCV, and the message would be deleted there before he could see it (again).
If Scout had been changing to fast ships (movement 6+) all the way, the X-boats would never had caught up to him. Also, if Du'Frey had designated his message for "French Arm" propagation, only, then it would not have followed Scout to Earth (which is in the "Core Arm").
This can lead to some interesting adventures, as PCs attempt to outrace a message up or down an Arm. One group of PCs, having discovered a Tantalum strike on a world, may try to get a message back to the Company's Homeworld to buy up all the shares of stock before the news of the strike drives prices up. Another group, fleeing Earth just ahead of the law, may try to outrace their own "wanted" posters. Note, however, that any group of PCs will probably be foredoomed to failure in trying to beat XBs or CMs, since they would have to have multiple fast ships (Merimee CMs have a movement rate of 6), and stopping to discharge means losing the race. Competing with the resources of Nations and MegaCorps is very, very tough...