SPIT (spam over Internet telephony), sometimes known as vam (voice or VoIP spam), is unsolicited bulk messages broadcast over VoIP (Voice over Internet Protocol) to phones connected to the Internet. Although marketers already use voice mail for commercial messages, IP telephony makes a more effective channel because the sender can send messages in bulk instead of dialing each number separately. Internet phones are often mapped to telephone numbers, in the interests of computer-telephony integration (CTI) but each has an IP address as well. Unscrupulous marketers can use spambots to harvest VoIP addresses or may hack into a computer used to route VoIP calls. Furthermore, because calls routed over IP are much more difficult to trace, the potential for fraud is significantly greater.
SPIT is not much of a problem yet, simply because IP telephony is not widely used. However, experts expect that the technology will become increasingly common over the next several years, thus making it much more attractive to spammers. According to Richard Tworek, CEO of Qovia, a company that makes equipment for monitoring VoIP, the question is not if SPIT will become a problem, but when. Quoted in an Internet News article, Tworek said that "SPIT becomes an issue when you don't have to go out over the traditional telephony lines. As soon as my VoIP system touches the Internet cloud, that's when it starts to become interesting. We predict it's going to happen, much as spam e-mail did." A number of vendors and organizations, including Qovia, are developing products intended to address the problem.