Whammy #1Despite the illegality of applying a state tax (of any kind) to an interstate purchase (in direct violation of U.S. Constitution's Commerce Clause found at Article 1, Section 8, Clause 3), Amazon.com has capitulated to Massachusetts' harassment. As of November 1, 2013, Amazon.com will begin collecting the state's sales tax on purchases sold by Amazon.com. This does not include third party vendors which sell their product through Amazon.com's website, who are responsible to handle their own taxation (if any).
The problem I have with this is that is really is illegal. Until such a time that Congress actually passes a law granting states the authority to apply their intrastate taxes to interstate sales, these states are in willful violation of our Constitution. There are exceptions this that have been allowed by Federal Courts, but Amazon.com (nor most online retailers) does not have a business that operates in such as way as to fall under these exceptions. Besides that, there are ambiguities that Congress needs to resolve. Allowing taxation of purchases that do not originate within the state may be an open door for states to outright tax purchases that have no origin or destination within their own territory, but are rather just passing through.
There are a lot of nonsensical justifications for taxation of interstate sales, and there are a lot of good reasons to not allow such taxation. I would go into detail here as to why, but I've actually covered this pretty well in a previous article about California's similar attempts to harass Amazon.com and other online retailers.