; or (G) business activities directly relating to such person's potential or actual purchase of goods or services within the State if the final decision to purchase is made outside the State. (c) Protection of non-Sellers A State may not impose or assess a sales, use, or similar tax on a person or impose an obligation to collect or report any information with respect thereto, unless such person is either a purchaser or a seller having a physical presence in the State. 3. Dispute resolution The district courts of the United States shall have original jurisdiction over civil actions to enforce the provisions of this Act, including authority to issue declaratory judgments pursuant to section 2201 of title 28, United States Code, and, notwithstanding the provisions of section 1341 of such title, injunctive relief, as necessary to carry out any provision of this Act. 4. Definitions and effective date (a) Definitions For purposes of this Act: (1) Marketplace provider The term marketplace provider includes any person, other than a seller, who facilitates a sale. For purposes of this subsection, a person facilitates a sale when the person both— (A) lists or advertises products for sale in any forum, including a catalog or Internet Web site