Yeah, whatever news site reported the co-op thing must have been working off old info. I assume whatever other mode they had in mind got added into the Mutation mode instead.
No, their blog two days before mentioned it, it must just be delayed or something, maybe we will hear about through some 3rd party new site since valve doesn't want to tell us whats up.
PC has names of some future Mutation games coming. Topping Realism VS is kinda hard, in my book. But the idea of Survival VS has me happy in the pants.