Spam mail is theft of service.
We are the ones paying for our connection, our disk space, and the time it takes to read or delete these messages. Spam mail not only consumes massive amounts of disk space but also bogs down mail servers and eats up a network's bandwidth, slowing down everyone's service. E-mail addresses can be pulled from newsgroup posts, web pages, irc clients, web browsers and from other Internet software. It's also possible that your address was added to a list from a form that you filled out someplace on the World Wide Web. The best way to prevent getting spam or getting added to mailing lists is to keep your e-mail address private.