This one point about the fediverse that I find essential to consider when thinking about reliability. Distributed ownership of servers drastically decreases the chances of the fediverse as a whole going down (not considering differences in the reliability of individual servers). But each individual server has a much higher chance of going down than say an individual subreddit. This is a subject I'd very much like to understand better, but it's clear it has implications to the chance of any given post getting lost.