According to Engler and Cellucci, "Ernst & Young concluded that 63% of total e-commerce sales to consumers are sales not taxable in most states". As for the taxable sales, "that same study also found that 60% of the taxable business-to-consumer Internet sales are substitutes for other types of sales, such as mail-order catalog sales by out-of state vendors, that do not currently generate sales or use tax revenue".
Proponents for Internet tax also argue that "it is not a new tax" but the enforcement of existing laws that give mail order stores the right to collect sales tax (Senate Nixes Sales Tax on Catalogue, Internet Sales 1).
Moreover, sales of the brick and mortar store continue to grow despite the flourishing of online stores (Engler and Cellucci 1-3). A brick-and-mortar store is able to provide consumers with service that the online store is unable to offer, such as getting to try the goods or see it physically before deciding to buy it.
Furthermore, Internet taxes would require the electronic tracking of purchases (Engler and Cellucci 3).