It`s official, the Playstation 3 and Playstation 4 versions of Diablo 3 will not be able to connect to Blizzard`s Battle.net. So in essence you won`t have interplay between Playstation Network and Battle.net which means no interplay between the platforms. The interesting thing though is PS3/4 players of Diablo 3 won`t always need to be connected to play either.
From Blizzard`s Diablo 3 forum:
"While we think cross-platform play would be awesome, there are currently no plans to allow connectivity between PlayStation Network and Battle.net (this is pretty standard for most games that have PC and console support). As a result, the characters on your Battle.net account and PlayStation account will also remain separate.
In terms of allowing an analog controller hookup for the PC, we don’t have any plans for that kind of support right now. Similarly, since Diablo III for console was designed with a controller in mind, the PlayStation version of Diablo III will not support USB mice or keyboards."
apparently the Playstation 3 version is "much further along than the Playstation 4 version, no released date has been announced just yet