I just read this point in a comment and wanted to bring it to the spotlight.
Meta has practically unlimited resources. They will make access to the fediverse fast with their top tier servers.
As per my understanding this will make small instances less desirable to the common user. And the effects will be:
Meta can and will unethically defedrate from instances which are a theat to them. Which the majority of the population won't care about, again making the small instances obsolete.
When majority of the content is on the Meta servers they can and will provide fast access to it and unethically slow down access to the content from outside instances. This will be noticeable but cannot be proved, and in the end the common users just won't care. They will use Threads because its faster.
This is just what i could think of, there are many more ways to be evil. Meta has the best engineers in the world who will figure out more discrete and impactful ways to harm the small instances.
Privacy:
I know they can scrape data from the fediverse right now. That's not a problem. The problem comes when they launch their own Android / iOS app and collect data about my search and what kind of Camel milk I like.
My thoughts:
I think building our own userbase is better than federating with an evil corp. with unlimited resources and talent which they will use to destroy the federation just to get a few users.
I hope this post reaches the instance admins. The Cons outweigh the Pros in this case.
We couldn't get the people to use Signal. This is our chance to make a change.
Can small instances handle the traffic that Threads will be generating? I imagine small instances may get overwhelmed by bandwidth / cpu constraints, due to not having the budget that Meta has. Smaller instances that get bogged down might find people migrating to Threads simply because it will be able to handle the load.