> Aside: 50000 concurrent requests on a single thread, huh? :) Unless I'm missing something, that's 50 seconds assuming a request takes only 1ms to process. Sounds like magic.

1ms to route a chat message is plenty.

e.g. on a single AWS m1.small prosody[1] can process 40,000 stanzas per second.

[1] http://prosody.im