People spoke of deliberate closure, to cause a migration to the new game, while others thought servers had been moved from one to the other for less sinister reasons but with the same end-result. Your world was no longer a vibrant place, riddled through with the lives (and deaths) of others.
No messages, no invasions, no human helpers, no ghosts, no bloodstains. The day that Dark Souls III arrived on Steam, the multiplayer functionality for Dark Souls I mysteriously died.