[Clent]

That tweet does not claim 20,000 is a record.

The event also did not reach 20,000, it "almost" hit it.

[pg314]

You’re right. I misinterpreted ‘record usage’. I found a 2013 blog post [1] claiming a 143 thousand tweets per second peak.

[1] https://blog.twitter.com/engineering/en_us/a/2013/new-tweets...