Spam is a slang term for unsolicited commercial email or junk email. Spam and spim are cousins: Spim stands for “Spam over instant messaging," and refers to unsolicited instant messages. Spim not only disrupts your chatting, but can also contain viruses or spyware. You can prevent spim by blocking any messages from sources not on your contact list. Your Internet and email provider can help you to prevent spam, and today most anti-virus programs include spam protection features.