I wouldn't be surprised if a good chunk of them aren't Twitter employees, but subcontractors somewhere. At least that's what plenty other social media sites do.

Well yeah, what else about Twitter would require that much raw manpower?

Ad sales, advertising relationship management, ad analytics for those relationships.

Isn't content moderation the biggest challenge at Twitter?

We've created a new class, of tens of thousands of people all over the world, who spend all day censoring content in realtime.

Eventually there will be giant censorship service corporations lobbying government for more restrictions on speech, and for them to be more complicated and confusing (to make them more difficult to in-house.)

No, we’ve created a class of global citizens whose only job is to handle, without protection, the torrent of psychological toxic waste we create every single second of the day. The vast majority of the work they do is to act as an ablative shield for all the horrors humanity can pour into the internet, and they do it for a fraction of the remuneration of a single social media company SWE, even when they’re onshored. What the rest of us see as “censorship” is the tip of the iceberg — the stuff that isn’t so horrid as to get weeded out immediately and so ends up in the “user-initiated moderation” category. Everything below that, if we weren’t destroying people’s minds and emotional well-being for outsourced pennies on the hour, would make the Internet so radioactive for every single user that an open WiFi point would be considered a crime against humanity.