Mastodon

The fragmentation that occurs as a consequence of this decentralised way of conducting social media is probably going to be the natural state of the fediverse for years to come. By its very nature, being decentralised, federated instances are not going to amass hundreds of thousands or millions of users from all (most) walks of life, and only appeal to those with a certain type of mind with nerdy, freedom-centric, and dedicated tendencies. By its very design, it's not going to catch on most people.