"Spam" is the use of electronic messaging systems to send unsolicited bulk messages, especially advertising, indiscriminately. While the most widely recognized form of spam is e-mail spam, the term is applied to similar abuses in other media, such as mobile phones.
Spam is flooding the Internet with many copies of the same message, in an attempt to force the message on people who would not otherwise choose to receive it. Most spam is commercial advertising, often for dubious products, get-rich-quick schemes, or quasi-legal services. Spam costs the sender very little to send (most of the costs are paid for by the recipient or the carriers rather than by the sender).
Mobile phone spam is directed at the text messaging service of a mobile phone. This can be especially irritating to customers not only for the inconvenience but also because of the fee they may be charged per text message received in some markets.
The term "SpaSMS" was coined at the adnews website Adland in 2000 to describe spam SMS. To comply with CAN-SPAM regulations, now SMS messages have to have the options of HELP and STOP, the latter to end communication with the advertising spam altogether.