E-mail—can't live with it, can't live without it. Con artists and real artists, advertisers and freedom fighters, lovers and sworn enemies-they've all flocked to email as they would to any new medium of expression. E-mail is convenient, saves time, brings us closer to one another, helps us manage our ever-more-complex lives. Books are written, campaigns conducted crimes committed-all via e-mail. But it is also inconvenient, wastes our time, isolates us in front of our computers and introduces more complexity into our already too-harried lives. To skeptics, E-mails just the latest chapter in the evolving history of human communication. A snooping husband now discovers his wife's affair by reading her private e-mail—but he could have uncovered the same sin by finding letters a generation ago. Yet E-mail—and all online communication—is in fact something truly different it captures the essence of life at the close of the 20th century with an authority that few other products of digital technology can claim. Does the pace of life seam ever faster? E-mail simultaneously allows us to cope with that acceleration and contributes to it. Are our attention spans shriveling under barrages of new, improved forms of stimulation? The quick and dirty E-mail is made to order for those whose ability to concentrate is measured in nanoseconds. If we accept that the creation of the globe spanning Internet is one of the most important technological innovations of the last half of this century, then we must give E-mail—the living embodiment of human connections across the Net—pride of place. The way we interact with each other is changing E-mail is both catalyst and the instrument of that change. The scope of the phenomenon is mind-boggling. Worldwide, 225 million people can spend and receive E-mail. Forget about the Web or e-commerce or even online pornography: E-mail is the Internet's true killer app—the software application that we simply must have, even if it means buying a $2,000 computer and plunking down $20 a month to America Online. According to Donna Hoffman, a professor of marketing at Vanderbilt University, one survey after another finds that when online users are asked what they do on the Net, 'E-mail is always No. 1.' Oddly enough, no one planned it, and one predicted it. When research scientists first began cooking up the Internet's predecessor, the Arpanet, in 1968, their primary goal was to enable disparate computing centers to share resources. 'But it didn't take very long before they discovered that the most important thing was the ability to send mail around, which they had not anticipated at all', says Eric Auman, chief technical officer of Sendmail, Inc. What does the first sentence of the passage mean?