Martindale Empowerment, a Virginia corporation, engaged in the business of providing commercial electronic-mail service to advertisers. Martindale regularly sent electronic advertising over the Internet in the form of e-mail to e-mail addresses throughout the United States. In September 1998, however, America Online, Inc., the largest commercial online service in the nation with more than 16,000,000 individual subscribers, implemented various mechanisms to block advertising messages that Martindale had been sending to AOL subscribers for nearly two years. AOL succeeded in blocking most of those transmissions by Martindale. Contending that Martindale was using deceptive practices in an effort to mask the source and quantity of its transmissions and thereby avoid AOL's blocking and filtering technologies, AOL sued Martindale on a variety of legal theories. AOL sought an injunction against Martindale's practice of sending unsolicited bulk e-mail advertisements to AOL subscribers. Martindale responded with a counterclaim in which it alleged that AOL had engaged in monopolization, in violation of § 2 of the Sherman Act. According to Martindale, AOL had established itself as the only entity that could advertise to AOL subscribers. For purposes of the first element of a monopolization claim- monopoly power in a relevant market-Martindale contended that the relevant product or service market was e-mail advertising. Was Martindale correct in this contention?