
What this feature allows you to do is pre order the digital game before release and download it in advance to your system, and when the game gets its official release you will be able to jump right in and play it.
Sorcery is the first title to offere this and apparently we'll be seeing more 'big titles' offer the same.
This is just one of the myriad Steam features that consoles were lacking, so I'm glad we're moving in the right direction. I'm a bit confused as to why they wouldn't have done it for the digital ME3 release. Anyway, good stuff!
http://www.thesixthaxis.com/2012/05/16/eu-psn-store-gets-steam-like-pre-order-functionality/












