For a brand new channel out of the gate, it's not doing horribly. It's on limited systems, and apparently only in SD on most.
Once they add carriers, and go 100% HD, the word of mouth will probably cause a bit of a boost. People are tired of the crap that is broadcast news in the US. It's either agenda-driven extreme viewpoints like Fox and MSNBC or dumbed down news for idiots like CNN. (Although, they're all pretty dumbed down.) And, they all spend far too much time on fluff and nonsense (Beiber, Kardashian, etc).
There is a solid core audience for NEWS. Actual NEWS. News about newsworthy things. In depth. With substance. And, as soon as they make it palatable for my eyes with HD, I'll be jumping all over it.