Google Sync was launched earlier this year and allowed you to sync your Gmail contacts and Google Calendar with your mobile phone. Google has now added a new feature to the service, something that users have long wanted: Gmail push support for the iPhone, iPod touch and Windows Mobile. To use Google Sync, you create a Microsoft Exchange account on your iPhone or Windows Mobile phone and updates are pushed directly to the Mail app, no third party software is required. If you want to enable push e-mail on your iPhone, you must also go to “Settings”, then “Mail, Contacts, Calendars” and set “Fetch New Data” to “Push”. This will negatively impact your battery life because a connection will be maintained with Google’s server at all times.
Push e-mail maintains an always-on connection with the e-mail server, which allows the server to “push” new e-mails to your client when they come in, giving you access to new e-mails second after they are sent, rather than having to wait for your client to ping the server and “pull” any new e-mails.
[Image from googlemobile.blogspot.com]