If you ever go to www.gmail.com, and someone sends you an email, it automatically appears. This is not because of polling, its because it keeps a idle http connection simular to comet.
No, that's not correct. The web interface is in fact polling from the web browser/java script. The web interface does not support IDLE.
The chat feature of the web interface uses a open connection to let your buddies know you are on line, but this does not affect gmail. Gmail polls, and if you have the ability to watch your own traffic (wireshark) you will see this polling for mail.
If you connect to gmail with a competent email client you can get idle, the the iphone does not support that either.
