@Temrin e.g. I followed you after you sent your first toot, so by default my feed just shows nothing: https://social.kithop.ca/media/XAHnh1qtpOZpoRE7JsQ
However, if I click your profile picture, it opens a tab with your actual feed as it is on the mastodon.social instance, which shows everything you've made public:
@Temrin Typically, think of following someone as more subscribing to all *future* content from that point. The reason being, with no real central server (it's all decentralized/federated), your instance basically sends a request to their instance going 'please send me copies of everything this person makes public so I can include them in my feed'.
@Temrin You can imagine after a couple years, you don't want to be 'please send me all their old stuff for the past X years too' unless you go digging for it, hence having to actually visit their profile page on their home instance to see 'old' stuff.
This is Kithop's private, invite-only instance - hosted on FreeBSD in Canada.