John does not have emails or messages to delete. In his time there are telegrams - wires. These are not deleted, erased or otherwise, and generally they are used for business or for emergency.
In his time, the regular contacts made with friends, loved ones and acquaintances are the post. Again, there is not house-to house delivery service, but rather what we would now call 'general delivery' at a post office or general store, perhaps a railway station or telegraph office. If one has not called for one's letters within a certain number of days, then a notice was put in the newspaper.
It is possible to follow John from town to town by these notices of letters he had not collected. Here is a list of people whose correspondence John would never fail to collect, whether he had moved on to another town or no:
1. Mattie Holliday
2. John S. Holliday
3. Robert Holliday
4. Miguel Otero
5. Lee John White
6. Lee Smith
He would have collected letters from Wyatt, but they never came; from Morgan, but he was dead.