Communications

As human beings who are, more or less, confined to living on a single planet and having discovered no reason to believe we aren't the center of attention in the universe - it's incredibly difficult for us to imagine what communications and the infrastructure of a galaxy wide society might be like. 
It only becomes MORE difficult if you're from a small country that is doing well. 
We humans weigh everything we observe against what we already know and draw assumptions and conclusions based on that. Some things are so built into our understanding of society that we cannot imagine a society without these things anymore. 
It becomes unrealistic to us. 
This isn't the case in all settings however - just imagine how complicated communication was just 500 years ago - no phones, no internet - no nothing. 
Only the option of word by mouth or written letters existed back then. 
This reality is probably likely in any medieval setting - but we could see similar situations even in the most advanced Sci-Fi settings, because, the distance, across which information is required to travel, - changes. 
== Spage Age Science Fiction ==
Obviously, methods of communication in a Space Age science Fiction setting are going to be dramatically more advanced than before - but the difficulty of successfully communicating has also increased heavily. 
=== Priority One Data Transmissions ===
Priority One Data Transmissions (P1, P1 Communications or P1 Mail) is the act of transmitting data through quantum entanglement. This is highly expensive to set up, and only allows communication between two points - which is why - most of the time - P1 communication is only partial - dipping into other methods too. 
Quantum Entanglement communication involves the act of separating two particles that will always retain the same relative position in comparison to the other particle. By manipulating the position of one particle, and observing the other, one can essentially transmit data. The effect is immediate and if done by a machine - very fast an efficient - how ever, as mentioned, it is only possible between two specific points - namely the two particles. 
There is such a thing as a Quantum Entanglement network - people transmit data by other means to the network, and it is in turn communicated to the right general region of the galaxy, after going through a server hub, and then by other means to the recipient. 
So to summarize, Quantum Entanglement is practically instantaneous or very close to - the distance having no real impact on the speed of transmission, though usually reserved for those who have permanently bought access to the services or Government related. 
=== Priority Two Data Transmissions ===
Priority Two Data Transmissions (P2, P2 Communications or P2 Mail) is the act of sending data through Hyper Space. There are certain ways that this is possible - namely via stations that are constantly inside Hyper Space, transmitting to each other - and eventually converting the data to another format that cannot exist in Hyperspace and as such is ejected and immediately picked up by a Station in Real-Space at the same location - then transmitted on to the recipient.
This means of data transmission can take as long as 48 hours to arrive - but this means of data transmission isn't typically very available outside the Hyper Lanes and a few otherwise well-used Hyper Routes. It's commonly closer to being instantaneous - provided the sender isn't at the very other side of the Galaxy. Most information spreads from the middle, meaning 24 hours is typically the actual longest time. 
P2 Communications is occasionally set up in a more limited than usual fashion in fringe space - often smaller services, capable of only receiving a limited amount of data per day. 
Any satellite or station can technically be upgraded with a Hyper Communication module, enabling P2 Mail, and then it's simply a matter of registering with the local post service and prioritizing message broad-casts (small devices do this by means of actual subscription - medium devices do it by choice of exclusion and prioritizing - larger devices can usually handle the bulk). 
=== Priority Three Data Transmissions ===
Priority Three Data Transmissions (P3, P3 Communications or P3 Mail) is the act of sending data through a combination of wireless transmissions (waves) and optical (light/laser) beams. This time of transmission is very slow as it travels at the speed of light at most. 
Mostly useful within orbit or from one point in a solar system to another. It's not at all unreasonable to imagine transmitting this way from one solar system to another - with considerable delay, provided the systems are close. 
In Fringe Space, this is the what most have available. Most places still divert a lot of non-priority traffic to these kinds of networks, because it helps unburden the higher networks.