We've gone thru this discussion about 6 times over the years including that long thread started by that woman who went on and on about the importance of big red buttons.
So I doubled the size of my "add to cart" buttons, made them red and much better looking. Copied and slightly improved a major retailer's button (Target's perhaps) that she loved... and saw absolutely no change in any metric.
Our button wasn't so bad to begin with. And I have seen a very few tiny bad ones on various sites. But in my opinion the button is a trivial element of ecommerce success, especially nowadays with most consumers knowing how web shopping works.
>>In the UK, we have shopping trolleys, not carts!
yes but the word cart is the defacto web standard.
OT.. i'm in the uk and of course in the uk the term delivery is standard not shipping - however i think that the internet has made the word shipping more normal, i get uk customers very often using the term shipping in emails to us.