If you're starting a brand new account on a Fediverse server, it's not a good idea to post lots of content before you have followers.
The only people who can see your posts on the Fediverse are those on your server, those on other servers which have at least one person following you, or those who see your post shared.
If you post all your best content up front on a brand new account with no followers, no one outside your server will be able to see it. Even if they follow you later, the posts you made before that will not be visible to them, because Fedi platforms don't backfill old posts on accounts you follow.
It's much better to gradually add content as your follower numbers grow.
You only need one follower from a server in order for everyone on that server to see your post. Even if you only have a dozen followers, that's up to 12 other servers that can see what you post.
(Sorry for repost, I phrased original post really badly!)
@freeschool @liwott
Yes, backfill is where your server automatically loads some or all older posts.
As long as posts have the correct permissions (for example public), there's nothing stopping servers from backfilling. It's entirely down to the software designers to decide if their platform backfills.