The Core

One piece of legislation that lawmakers might try to attach to this bill [December government funding bill] is the Marketplace Fairness Act (MFA), or some version of it. Under this separate bill, state governments would be granted the power to levy taxes on various remote vendors that have no physical presence within their state.

http://www.freedomworks.org/content/internet-should-remain-free-taxation?source=FWFBinternettaxBlog