Something interesting has happened with the Morespace project. Up to this point, you had to provide some basic information in order to download the free electronic versions of our chapters. After receiving a complaint, and discussing it with the authors, Todd decided not to require that anymore. Several people in the comments have disagreed with the decision, but we've sold a few more books recently. Maybe there is a causal connection there or maybe it's just coincidence, but there is something to be said for making products simple to try and simple to buy.
I believe that the frictionless sale will almost always win out over one with friction. The only exception I can think of is a sale based on passion (need or want).
A goal of any small business should be to minimize friction in the sales channel.
Ed Sim had something about this a few months back “The less friction you have in your sales and delivery model, the easier it is to scale. The easier it is to scale the faster and more efficiently you can grow. ”
http://www.beyondvc.com/2005/09/skype_and_siebe.html