Re: Poll: How effective is learning aikido through a purely visual media (videos, DVD
You can learn more of Aikido by being physically connected to a competent instructor with your eyes closed that you ever will by watching alone, regardless of the medium.
All senses are vital to the educational process, and as many as possible should be engaged at all times. You need to develop the proper set of eyes to see what is REALLY going on, but the only way to do this is by feeling, seeing, hearing, tasting, and smelling it. Only then with the "dai rokkan" kick in.
But since your question stipulated "purely," my answer has to be a big fat :-p~