Also known as junk email or sms messages, these are unsolicited messages, typically advertising, sent in bulk which are in some way detrimental to the recipient.

In addition to email spam, there can also be spam in Usenet news, search engines, wikis, forums, blogs, popups and any type of image or text on the web. Junk mail can also target mobile phones (through text messages) and instant messaging systems, for example Outlook, Lotus Notes etc.