I have very few abandoned carts if this is what you are asking. My checkout is different and does not know if someone adds it to a cart until they begin the checkout procedure but I may lose 1 in 10 after that point. Now if only I could have those same conversion ratios.
Typical conversion rates by (a) definition are about 1-2% from our experience and general statistics. It's quite sad comparing to offline stores rates, that are variyng from 10% to 90%. But note that almost all visitors of offline stores are highly targeted.The other reason is that often a human needs a human to talk to before making a purchase. Online store looks like an empty space with shelves loaded with goods but without a salesman. People feel themselves abandoned and confused while they cannot make they way through all obstacles on a site and prefer to switch to another site with better usability or even go to an offline store. There is a software solution solving this problem of e-commerce and a couple of others as well. When people get a possibility to use a live support at any page of your site, they commonly do it, if it looks handy.
P.S. Excuse my Engrish btw, i now it's quite far from an ideal
[edited by: lorax at 2:59 pm (utc) on Nov 19, 2011] [edit reason] removed promo [/edit]