Recently I was talking with my friend Jim Yaghi (a computer scientist-turned-Google-AdWords-wizard) about testing sales letters against things like video, text, audio, etc. And we got to rapping about all the online video hoopla.
Does it REALLY always out-covert text? Is it REALLY the way all sales letters are gonna be ever? Will it REALLY be something you "must" use or die on the vine?
No, nope and nuh-uh.
In fact, let's play fantasy land for a second. Let's assume video is best when all other things are equal. Does that mean YOU should use it? Not necessarily. For example, if you're better at writing, but can not make a decent video to save your life (due to technical and / or presentation issues, for example) then video probably will not be your best bet. (Maybe, maybe not.)
Same with audio, too. (Or whatever you're testing.)
I have seen repeatedly in multiple business ventures that sending a full email to a list out-pulls (in sales) sending people a short teaser sending people to a blog post for the full message. But you know what? World class Internet marketing coach Glenn Livingston told me in an interview it's the opposite for him. Why? Who knows? Maybe it's his market? Or maybe I'm just better at persuading in text and he's far better at persuading in audio on a blog? (He kicks gluteus rumpus at audio.)
Any, here's the point: It all depends on you, your market, personality, technical know-how and savviness, writing skills, presentation abilities, and so on and so forth. There's no one size fits all.