> As for your pick an instance, you have to research them all, figure out which will let you follow others and which has sane mods.
No you don't. No one does this. No one needs to do this. You can literally just find an instance you like and join it. If it doesn't work out, you can leave. It's not even that hard to export all of your follows on Twitter and import them. More difficult than on other social media platforms? Yes, but only because those platforms don't allow it.
> Until picking the instance with Mastodon doesn't matter (either it is trivial to move between instances or there is a clear winner so everybody picks it), it will stop way more people from signing up.
You don't even have to pick an instance. I have a separate account on multiple instances, many people do. This isn't a zero-sum game, instances aren't competing against one another. No one has to pick a winner.
>it is well known that if there are more fields on a form, fewer people will complete it.
The form for every instance I've seen is no more complicated than elsewhere. Pick a name and password, maybe a note to say why you want to join. Millions of people fill out more complicated forms all the time.
I understand this is the popular wisdom from having seen numerous threads about Mastodon, Peertube, etc. around here, and I've even made the argument about it being too complicated for most users myself. But practice doesn't seem to be bearing that out.
The issue here, to me, is whether something can count as a "replacement" for Twitter unless it replaces it entirely. A lot of people on HN seem to believe that unless you have a single service that captures the entirety of Twitter's userbase then you aren't a "serious" contender, but I would disagree. Another poster here has argued that we're seeing a paradigm shift away from monolithic services towards fragmentation, and I think that's true, and has been taking place long before Musk and his Twitter shenanigans. Nowadays, people use Twitter and numerous other platforms, Discord, in-game services, etc. Twitter's network effect means less when all of your friends are also on a dozen other services, and identities are generally distributed.
I think it's perfectly legitimate to say that Mastodon is a replacement for Twitter even if it is only for some people.