Verizon Wireless, the #2 US mobile carrier, has won a permanent injunction against Passport Holidays, a Florida company, to stop them from sending unsolicited text-messages Verizon subscribers. The lawsuit was a result of 98,000 messages being sent to Verizon customes in October. At an average rate of 5¢ per text-message, this makes for approximately $5,000 in fees that Verizon charged its customers due to the spam. Verizon also received a $10,000 judgment from Passport Holidays.

Text-messaging spam has different economics that ordinary email spam. In addition to the annoyance of receiving an ad on the cell phone, many mobile subscribers are charged for each incoming text-message (in fairness, many plans have included a number of free in/out text-messages while other plans have free incoming messages.) Thus, mobile phone spam presents a more serious economic threat than email spam and it is good to see providers become active in prosecuting this type of threat.

How effective is text-messaging spam anyway? Users receive a short message on their mobile phones that tries to sell them a vacation cruise and lists a call-back number for people to dial. How many people actually do through the trouble to dial that number despite (possibly) the annoyance and (hopefully) suspicion?