If you live in USA and run an online store then you know that most states require merchants to collect taxes for online sales. It can be quite annoying without some proper features. But shopping cart software has such feature. Thanks to it you wouldl no longer need to worry. Your shopping cart software will calculate taxes.
Another quite useful option that shopping cart software has is the Customer Management. This option lets your shoppers see their previous purchases.
It is all thanks to the feature of the shopping cart software that recognizes customers if they return to your site. It does not matter if they come back after a month or a year.
You will be able to view how many times the customers visited your page in a week or since your shop was created.