Turns out around 700 GB of media storage on mastodon.social was being consumed by multiple Twitter "bridges" running on different domains, reposting Twitter users' tweets into the fediverse as far as I'm aware without their (the Twitter users') participation or knowledge.

That's 10% of our media storage accumulated over 6 years. At least cross-posters set up their own accounts, that's still legit use. This, it just feels so wasteful. How Twitter even gives out API keys for this, I don't know.