24/7 Mail, the e-mail marketing unit of New York-based 24/7 Media Inc., announced last week that it will manage the Economist.com's quarter-million name e-mail list. The Economist.com is the Web site for The Economist, a London-based publication. The site claims to have more than 800,000 registered users. The deal boosts 24/7 Mail's international e-mail lists to more than 350,000 names. Under the terms of the agreement, 24/7 Mail will manage and market the list to European and U.S. companies. The Economist.com and 24/7 Media would then share the revenues generated from the sale or rental of the list.