How does the live, real-time typing work in Google Wave?

Question

I\'m sure Wave doesn\'t poll the server every millisecond to find out if the other user has typed something... so how can I see what the other person is typing as they type? And

Answer 1

Persistent HTTP, Comet

Keep your HTTP connection alive and send characters as they are typed

*Edit in 2014: also, take a look at WebSocket and HTTP/1.1 Upgrade header. Browsers started implementing this around 2010, so I'm adding this to original answer.