http://www.sba.gov/content/collecting-sales-tax-over-internet
This link might help explain it best. But basically it means, that if the business has an actual "physical" building, they have to charge sales tax for the state/county the building physically exists in.
So those business that are totally internet based and have no acutal physical store front can get away without charging the sales tax.
Great for the customer, but not so great if your the person that has a physcial store front and looses the sale because of the sales tax.
Personally I dont' mind the sales tax. I would rather pay that then have taxes taken out of my pay. Then I would only pay taxes on what I deem is absolutely necessary for me to have and if I dont' want to pay the tax on the item then I don't get it, Maybe thats the way it should be then higher priced items get taxed more. I mean hey, if the government says when I buy a new car next time it has to have a back up beeper, (who cares if it costs me more, right), so you might as well make the taxes on that higher (cause I'm not sure I'm going to pay a few thou extra for something I didn't want, and we all know its going to cost the customer that), and make the taxes in my paycheck go away.
Everyone keeps forgetting that this country is in trouble, the government spends money it doesn't have, bails out banks and car companies, give the rich tax breaks and taxes the rest of us more. If everyone paid what they owed, including everyone paid sales tax regardless, maybe we wouldn't be in this much trouble. But everyone wants to "get away" with not paying this and not paying that. Every little bit makes a difference. Whats the sales tax on a Hummer or a jet?! I know I'll never buy one, but you can bet the ones that do have figured out a way not to pay sales tax and anything else they can get away with, yet they can afford to pay it.