New Zealand (South Island)
Seth Kenlon is a UNIX geek, free culture advocate, independent multimedia artist, and D&D nerd. He has worked in the film and computing industry, often at the same time. He is one of the maintainers of the Slackware-based multimedia production project Slackermedia.
Authored Comments
As Strypy says, yes, if an instance you are using evaporates, then so does your user account. This is a reality of modern web services and probably why many people opt to use the multimillion-dollar providers; presumably, they'll never evaporate (not true, but it's the perception, and in practise, there does seem to be a trend that if a corner of the Internet fails, some greater entity will buy it out).
On the independent web, you have different ways to mitigate this risk.
1) First, you can export your data. Mastodon allows for this through its web UI and through its API. So if you were very concerned about losing past toots, or your list of friends, and so on, you could export the data on a semi-regular basis, and even script it through the API.
2) Alternately, you can run your own instance, or team up with some reliable group of people who you trust and run a co-op instance.
3) Many instances that have been brought up so far also have Patreon accounts, so if you want to help ensure an instance sticks around, throw money at it. Get to know the admin. Take an active role in your web use! Consumer culture tends to eat itself, so take this as an opportunity to be a part of the system you use.
Lots of options!
This is an amazing analysis of the strengths of open source. Thank you.