Taxing sales is an important way for governments to make money. Online sales should be taxed in the same way that sales at brick and mortar stores are taxed. There is no reason why online sales should be a special catetory. As online stores expand, this could be a greater source of funds for the government.
Online sales shouldn't be taxed in the same way brick-and-mortar stores do simply because it gives Internet retailers a disadvantage. Places like Amazon and Overstock revel in interstate commerce laws that currently forbid sales tax on purchases outside of the state where brick-and-mortar locations exist. If the federal government legalizes sales taxes for online purchases, then other industries that get advantages from subsidies must be dealt with. To be fair, the government must get rid of oil, gas and farm subsidies if online sales taxes will be legalized.