A con man gets conned into the job of postmaster by Ankh-Morpork’s patrician Vetinari. It’s either postmaster or death, and Moist von Lipwig finds out that he prefers the former.
This is as much about the clacks system, that was quietly introduced in The Fifth Elephant, as it is about the post system. Sure, the clacks system is a rival to the Post Office, it’s faster, seems less personal than a mail and is controlled by people who go over dead bodies to get even more money.
And yet, while trying to modernize the postal system, Moist von Lipwig realizes that the clacks are the future. For a short time he may get the heart and thus the ear of the people, but for the long term the clacks are much more important than the postal system will be.
Often a certain kind of fantasy seems to dwell on the past, relishing the fact that modernization is far away, but the Discworld series has proven to be a refreshing change, openly going for modernizations, with all the good and the bad. While many long running fantasy series are examples of diminishing returns, inversely the Discworld series has grown stronger with each passing year, and Going Postal sets a new height for excellence.