My father once received a letter from Algeria, with 3 words on the envelope : his first name, "Créteil" (the town where he lived, ≈100k inhabitants), and "France". Of course, in the 70s there was no Internet nor central database to find him, yet the postal service managed to deliver the letter. He was a very active social worker, managed a youth football team, etc. which made him locally well-known by his first name.
Nowadays, many people can't find anyone or any place unless their phone helps them. And postmen never stop to chat. Such a letter would not pass through the technology process, and probably not through the human network.
