My Mastodon client ( Mona) has the ability to fetch historic posts directly from the remote instance into the app. (Source to front end). Without leaving my client I am able to interact with older content from a profile, that predates the moment of federation. It circumvents the need for my instance to have fetched the content. This seems so efficient. The content is fetched directly from a place where it is already publicly available. My home instance does not need to bother with it. (2/3)