Does advertising on Twitter work? I am curious if engagement matters too much provided Twitter is delivering the results? Of course if it is not cost effective then they have a problem.
You're purchasing time from people that are busy, and productive, and have a life that on the whole it not completely virtualized. Compare that with Facebook and MMPORGs of sorts, and there are some highly successful virtual people who live real lives in mobile homes and shitty apartment complexes. Not to say their overall quality of life is bad, but maybe their balance is off kilter some.