Rafe (and our Lumia 925) is currently in New York, so we'll pass you on to our friends at Windows Phone Central to demonstrate this update:
In short, you can now optionally hover your hand like a Jedi over the display to turn on the Glance screen, which then gives you notifications and clock. Under those conditions, the Glance screen stays on for a minute or two, giving you a "peek" at the display. That's opposed to having it always on or timed. Call us crazy, but that is some awesome usage of the proximity sensor for motion detection. Kudos to Nokia for adding a feature to the OS where none existed before.
Pick up Display + Touch v1.6 here in the Nokia Collection.
It's pretty cool to have the choice on how Nokia Glance works to this degree of granularity, though of course there's nothing really new under the sun and this draws from ideas on Nokia's own Symbian platform (Big Clock, Sleeping Screen, even qooSaver), plus ideas from Samsung's Android phones and their use of the proximity sensor.
It still remains to be seen how Nokia Glance will function on the LCD-equipped Nokia 720 and 920 - here's hoping that 'Peek' is purpose designed for the power requirements of non-AMOLED screens, i.e. wave your hand over the 920's face and the clock will appear for a few seconds?