Some states do tax services (sometimes with some exemptions). Other states don't tax services, but do tax sales of digital goods, such as iTunes downloads, eboo

Some states do tax services (sometimes with some exemptions). Other states don't tax services, but do tax sales of digital goods, such as iTunes downloads, ebooks, or apps. There's no blanket "sales tax = physical goods" rule (it's not clear why there would be, especially in cases like ebooks vs. paper books).