Spam, also called junk e-mail, is unsolicited e-mail. Spam is an annoyance to the recipient and may contain computer viruses or spyware. It often advertises products that are usually not of interest to the recipient and are oftentimes vulgar in content. Estimates suggest that as many as one billion spam messages are sent daily. Many email programs have spam filters or blockers to detect spam messages and either delete them or send them to the “junk” mailbox.