Spamming is the abuse of electronic messaging systems to send unsolicited, undesired bulk messages. While the most widely recognized form of spam is e-mail spam, the term is applied to similar abuses in other media: instant messaging spam, Usenet newsgroup spam, Web search engine spam, spam in blogs, and mobile phone messaging spam.

Spamming is economically viable because advertisers have effectively no operating costs beyond the management of their mailing lists, and it has proved difficult to hold senders accountable for their mass mailings. Because the barrier to entry is so low, spammers are numerous and the volume of unsolicited mail has become very high. The costs, such as lost productivity and fraud, are borne by the public and by Internet service providers, which add extra capacity to cope with the deluge. Spamming is widely reviled, and has been the subject of legislation in many jurisdictions. Read more