Have any stuies been done about what sells best on a website, for the same product. What I mean is : Say you are selling tips on Gardening. Will these tips sell better in eBook, CD or Audio Tape form ?

Obviously, the last two must take a great deal more money to produce and send by normal mail, but, is there a proven marketing answer ?

Why am I asking ? Because I want to look at alternatives to eBooks for the future.

Thanks very much in advance for your opinions and information.

Ken Black
http://golfrevelations.com