I really dont understand some internet users, they are too lazy to fill out a form containing 20 boxes. I was never lazy to fill a form to register in a site and I am an internet buyer the last 4 years. As long as i want to register, i will no matter what.
Another thing is that the big online stores dont really care about this because they already have a huge database of customers so loosing 100 people a day and having registered 1.000 new, it's not a problem for them. It's into their buisness politic, they are aware and for sure they are trying to make the "future" client to registrer offering him some bonus after the sign up either some money or a discount.
I run a normal retail store in one of the bigest streets in my town, every day 50.000 cars pass by. I have a big projector pointing outside wich runs an advertising application with slides etc. (like powerpoint but by far more professional) and i have huge letters saying: If you come close and see this code (written with really small letters) and type it into our website coupon system then you get a discount in the products that i "deliver" in the projection. So people tend to register to benefit from the coupon code.
In conclusion i really dont care about people registering or not.I get enough customers through the way described above, i think all merchants can find a way to attract customers.