Battlefield 4's Battlescreen (also known as Battlemap) will only be available on Next-Gen Consoles and PC. Its a feature of Battlelog that allows you to use a tablet, mobile device, or PC to check stats, change loadouts, server browse, or view an interactive map while your in-game, all of which are in real-time.
Basically on PS3 or Xbox 360, all these features will be up to date with the last map you played on and not with anything you did in the match your currently in. Also changing loadouts on battlelog wont take effect until the match is over not to mention you wont be able to view to interactive real-time map of the game your in.
Battlelog's assistant producer, Jesper Nielson told of how Battlelog will entirely be Web-based now:
"Battlelog is powered by the web, and that has a lot of implications. There are a lot of different things you can do, things you can do faster, rather then building stuff in the native code. Its going to be a lot easier for use to actually update things from the in-game Battlelog then would otherwise be the case. You'd have to do patches normally; here we can actually do things almost by the flick of a finger."
This may also affect commander mode on current-gen consoles because to use it you need an interactive real-time map but that isnt confirmed (yet).
For more on it go to the full story at IGN.