Reddit used to be open source too the problem with centralized software like that is that even if you start up your own instance (and lots of people did) it's completely empty and it's going to STAY completely empty forever unless you also get users posting things, which they're not going to do because you're empty.

The idea of Fediverse is that you can break down that impossible barrier to entry by communicating with all the other sites in the Fediverse even as a brand new site. Even though when you start your Fediverse server it starts out empty, it can pick up all the content from every other Fediverse site in the world (gradually) and get you past that initial roadblock, treating you as a potentially valuable partner and not a competitor. And if a big site goes away, their content is still with you, and everyone else.

It's not going to magically get you users, but maybe you don't want users, and all you want is the content. Or maybe it will buy you enough time to get the users you want to get. No matter what, while it's not a magic wand and building an active community is always going to be hard, it's certainly a step above Reddit's retracted "open source" offering in the way that it tries to encourage and support people to start their own communities. It's more than just throwing some software at them and saying good luck, it's also giving you content, and communication, and hopefully eventually even more as it grows and matures into the future.

I am really eager to see what kind of content discovery / search / recommendations people can start building on top of Fediverse and ActivityPub, I think that's the next step. Reddit's search and community discovery has always sucked, and Youtube's recommendation algorithm has always been untrustworthy, and I think things like that tells us it's probably a hard problem, but I look forward to seeing what the platform can do.