The website for Dark Souls is at PrepareToDie.com.
You could make an argument that this is a reference to the gameplay mechanic that will see you spend time in the game as a "soul"; an astral being like state lacking in a physical body because it has died.
Anyone who's played Demon's Souls will shatter this delusion. The real reference here is to the reality that these games are utterly unforgiving and you are going to die. A lot.
The first game was awesome though; with some unparalleled atmosphere and compelling gameplay. If they've boxed any of that in here it's ending up on my shelf in short order.