A wider variety of opinions... Fediverse imo is known for tankies and progressives. I'm a progressive so I'm OK w/ the latter, but it can be an echo chamber at times.
Built-in audiences (Threads especially but also Jack founding a spinoff helps)
Similar to Linux, one of the benefits to open-source is plenty of forks and standards. This leads to a more fractured landscape at times and so it's rockier than the alternatives
I know it's not the main point, but I wouldn't call Linux fractured. Linux has multiple choices, but they all work fine unless you're going into an experimental realm or uncommon distros that beginners shouldn't be getting near anyways.