Window-shopping is just as relevant on the web as it is on the high street. Providing the customer with the ability to put items of interest aside, so that they can return to them once they are ready to complete the purchase, is a key function of a customer focussed web site.
This then means that the customer can return at any time and move the saved items into their current shopping basket and purchase them in the normal way. In addition, the list of saved items can act as a 'wish list' and be easily emailed to family and friends.