"What’s the future of Comet?" None.

It will be killed as soon as WebSockets get implemented.

WebSockets will bring the real-time web alive. It will be the greatest advance in internet since its early days.

Google Wave will ride on WebSockets. Web alerts will be the next gold mine. iPhone like push messages for email, feeds, etc., web chat without hacks, instant collaboration and much more.

We really don't understand right now the impact of the real-time web, but it will be pervasive.