I’ve set up a couple of single-user instances of fediverse apps (Mastodon, Lemmy). With Lemmy, I can post/comment to any community/thread I want that is federated, but I can’t seem to do that with Mastodon.
With that being the case, how does the content I post on Mastodon get shown to people on other instances (I know replying works differently). I feel like any top-level post I make on my instance is basically like shouting into the void, correct?
Also, if I were to set up a Pixelfed instance, would I have the same problem where my content doesn’t get shown to anyone (except those that follow me?)
Yes, your public posts will be delivered to the other instances in the relay(s). From there, anyone watching the Federated feed will see the posts. Also if your posts include hashtags then anybody searching for or following the hashtag should see your posts.