Confused about this DK tanking build.

[Tozers]

I was wondering around dalaran today and got confused over a DK tank I inspected. I have never seen this sort of tank build before and i wonder if someone could shed some light on it.
Looking at the build i couldn't figure the rotations or the need for Scent of Blood as a blood tank.
http://www.wowhead.com/talent#jMEGV0...LhxLZcx:0GiVMc

[Harmacy]

I see a lot of tanks with faceroll specs. It's disturbingly common even in raiding guilds.

[Dadodil]

It's just some random spec, nothing you should worry about. My guess is that the guy doesn't know what he's putting his points into.