We recently revisited the topic of whywent missing in September last year. The promised push technology was a service that would have allowed applications like instant message services to operate in the background while the iPhone is asleep or another application is being used. It was meant to take the place of multi-tasking that we are all accustomed to on our computing devices.
Now we are hearing rumors that that the long delayed push notification technology might actually become a part of the forthcoming Mac OS X Snow Leopard.
According to various sources this fits in with the future of support for open push messaging standards for Mail, iCal and Address Book -- all three of those applications are supposed to get Exchange Server messaging support in Snow Leopard. So taking iCal Server as an example it will be rewritten to support the XMPP standard. This standard would allow the push of new or updated calendar events rather than entire calendars to recipients.