The odd thing is that I thought a lot of 'sales' taxes were technically 'transaction privilege' taxes, nominally levied on the retailer. In theory, they could eat the tax, but generally, they pass it on to the customer.
One would expect that from an implementation standpoint, putting the onus on the retailer makes more sense-- there are fewer retailers to audit, and they keep detailed records for other reasons, making it simpler to sanity-check their claims.
Yeah, the Sales Taxes are levied on the retailer, but with the current crop of "Use Taxes" are the states attempt to regain lost income from web based interstate commerce.
Yes, they could eat the tax, but generally if you are not charging the customers tax (especially the ones that you do need to charge) you are also not going to simply give x% of your income away on top of the business income taxes, ect...
The biggest problem with this taxation issue is determining where exactly the transaction took place, . Should it be the customers computer, or the location that the business is registered or the location of the server that processed the web order (trust me, there is a group of people pushing for that, which would lead to offshore web shopping