I've run my own single-user instance since 2018 - the biggest downside is discoverability and community. Discoverability: With other users on the instance the

I've run my own single-user instance since 2018 - the biggest downside is discoverability and community. Discoverability: With other users on the instance the federated timeline is populated by posts from users that others on your instance follow, so you have to follow people a bit more liberally to discover other posts. Community: Instances also have a local timeline, which shows posts from others on the instance and this gives each one a slightly different vibe. With a single-user instance it's just your posts! But either way, you can still interact with pretty much anybody else in the Fediverse, and once you're followed by a couple of people your posts will go out to the federated timelines of other instances and you'll get interactions via that.