You've Got Mail!

The first networked electronic mail message was sent by Ray Tomlinson of Bolt Beranek and Newman in 1971. This year, according to market research firm Radicati Group, 3.8 billion email users worldwide will send 281 billion messages every day.

That's 3.2 million messages a second—hotel reservations, meeting notices, greetings from friends, product designs, receipts, flirtations, complaints, requests for help and, of course, spam. You may feel like a substantial number of them end up in your inbox.