Spamming is the use of any electronic communications medium to send unsolicited messages in bulk. While its definition is usually limited to indiscriminate bulk mailing and not any targeted marketing, the term "spam" can often refer to any commercially-oriented bulk mailing perceived as being excessive and undesired. In the popular eye, the most common form of spam is that delivered in e-mail as a form of commercial advertising. However, over the short history of electronic media, people have done things comparable to spamming for many purposes other than the commercial, and in many media other than e-mail. Spammers have developed a variety of spamming techniques, which vary by media: e-mail spam, instant messaging spam, Usenet newsgroup spam, Web search engines spam, weblogs spam, and mobile phone messaging spam. Spamming (the name of which derives from a Monty Python sketch about SPAM brand processed meat) is economically viable because it allows advertisers to shift their operating costs to the public, as Internet service providers must add extra capacity to cope with the deluge. Spamming is widely reviled, and has been the subject of legislation in a number of jurisdictions, including the U.S. CAN-SPAM Act of 2003.