In 2006, U.S. consumers received about 800 million text messages that they identified as “spam.” In 2007, we estimated the total was around 1.1 billion. Our estimate for 2008 is 1.5 billion.

At first sight, these numbers sound large, but remember that this is over an entire year and that there are some 200 million active SMS users in the nation. In other words, the problem is negligible, and nothing like the size of the email spam problem. The typical user receives “a few” SMS spam messages per year. Obviously some unlucky people receive considerably more, but many receive none at all. Compare the 2007 estimate with CTIA’s 2007 numbers for legitimate U.S. text messaging: Spam is about one-third of 1% (0.3%) of the total messages received.

Mobile service providers such as Sprint and AT&T Wireless are highly motivated to keep it this way, for obvious customer satisfaction reasons. The good news is that cell phone networks aren’t completely “open” like email is, so it’s much more difficult for a sender to anonymously send spam. (Note that we’re being careful to estimate the number of spammy messages received--this is the figure after the carriers have thwarted other attempts to spam. We can’t accurately estimate how many unsuccessful attempts there are, but it’s a substantial number--probably at least another 1.5 billion in the United States.)

Very few of these spam messages are sent from a real handset in the conventional way. Mainly they are injected via an SMSC (Short Message Service Center) or email/Web gateway, possibly from overseas.

For the most part, the cost to a consumer of receiving a spammy SMS message is only theoretical. Many U.S. users pay a monthly charge, which entitles them to send or receive a “bucket” of messages. Even for those who pay per individual message, the average number of messages per consumer is small--one or two a week. (The North American mobile market is unusual in this respect. The vast majority of countries’ wireless providers do not charge for receiving messages or calls. For example, consumers in the U.K., France, and Germany can receive as many text messages as they like, without charge and without fear of exceeding a monthly allowance.)

… Richi Jennings