More to do with mistakes and execution. Why did they take $70m in funding? That's a ridiculous amount of investment to take.
Why couldn't they monetize that amount of eyeballs?
Maybe the spam thing was working for them but I don't think they would have folded if so.
It'll be spun as a success "Acquired by Google yay!", but seems a pretty resounding failure to me.
 Definition: lots and lots -- 1T / month in summer 2011