Fediverse

Nothing

The purpose of federation is to build a network that no one entity can control. An evil CEO can enshittify their own server, but the damage they would deal is limited to their server. The rest of the network would still exist outside of their control, and users can easily leave their server to go elsewhere.

Smaller instances, being smaller are actually easier to moderate and have and easier time detecting those things than then bigger ones. Small instance many times are small, not because they're new but because they heavily moderate who can belong to their server and federate with their content.

It's the biggest instance that tend to have worst quality of moderation, thus being more at risk of things like AI scraping or bots.

There's a reason people who practically have been on the fediverse from the very beginning tend to tell you to avoid flagship and massive instances; those are a moderation nightmare, both to their own admins and to other intances' admins.

2- Most fediverse software have tool to block AI, bots and ads.

On what's stopping corporations from taking over the Fediverse....We are. Our ability to decide whom we federate with is stopping corporations from taking over.

Lack of interest from their part. Right now, they have nothing to gain, fediverse is "small fry", and if the attacks could be traced back to them, they'd have to deal with the PR shitstorm

What is stopping corpos from scraping everyone’s posts and stuff from the fediverse and train their AI?

They're probably already doing that

Nothing? In practice, if this were to happen on a noticeable scale it would mean Lemmy has gone mainstream. That said, within a federated system, it's entirely possible to create isolated, defederated webrings - for example, networks consisting solely of invite-based instances. If something like this becomes a necessity, it might lead to formation of multiple such webrings and they might even decide to federate with each other someday.