(CNET) -- I got my first SMS spam message last week and it infuriated me.
The mortgage-related text message was more than just a nuisance, like e-mail spam is. It also was a strong indication of how marketers have managed to invade every private communication space consumers have.
And it was frustrating that I didn't know what to do about it. Being an AT&T customer, I tried to register on AT&T's site figuring I could learn what to do and take action there. Unfortunately, it kept telling me that it didn't recognize my password, so I had to call customer support.
The support representative directed me to a different URL where I was able to log in and she tried to walk me through the site to the place where I could set spam-blocking settings, but was unable to because of some technical issue on her end. So she just changed the settings for me.
I called the four major U.S. wireless carriers to find out exactly what they suggest their customers do when they get SMS spam. Here is what they said, along with some other basic questions and answers people may have about mobile spam.
Customers can block text messages or calls from a specific phone number on its Web site here, as well as restrict the sources of e-mail that reach your phone on this site.
Customers can also reply to text messages by typing in "BLOCK" or "STOP" to prevent future messages from that sender, and call a customer service representative if further help is needed, said AT&T spokesman Mark Siegel.
Sprint wants customers to call customer service to report all spam messages so the company can modify its spam-filtering technology to block the phone numbers that are sending it, said Sprint spokesman John Taylor.
Customers should not reply to the messages, otherwise it verifies to the spammer that the phone number is valid, he said.
Postpaid and FlexPay customers can create their own filters and block chargeable text messages, MMS (multi-media service) messages, instant messages, and e-mail from being sent to their phones by calling customer service, spokeswoman Cara Walker said.
Customers can log into the site and sign up for Usage Controls ($4.99 a month) that allow them to block certain numbers from calling or sending text messages to the phone. And if customers text only with a few people they can create an alias address here for free and receive only text messages sent to that address, said Verizon spokeswoman Debra Lewis.
Verizon has filed eight to 10 lawsuits against SMS spammers over the past four to five years, and 20 lawsuits altogether involving telemarketers, she said.
What can I do to prevent unsolicited phone calls to my mobile phone?
To block spam phone calls, customers should register their mobile numbers with the U.S. Federal Trade Commission's Do Not Call Registry.
What are the carriers doing to block spam?
The mobile service providers said they are using antispam filters and antivirus technology to protect against the different types of mobile spam. They did not want to go into too much detail as to what technologies they are using.
Why am I getting spam?
Some people may be inadvertently opting in to receive text messages when they sign up for other services with merchants. Many free ringtone download sites are used to harvest mobile numbers.
Spammers also use auto-dialers that randomly generate numbers or try them sequentially. Because mobile phone numbers do not appear in public directories people should be careful who they share their numbers with. Be wary of sites that promise to remove numbers from spam lists because they are often set up to collect the numbers instead.
Also, read terms and conditions of sites and services carefully before giving out a mobile number.
Do I get charged for spam messages?
In general, consumers will not be charged for spam text messages and can get a credit if they report it to the company, on a case-by-case basis.
Is spam illegal?
While Verizon is suing companies for violating the federal Telephone Consumer Protection Act, which makes it illegal to use an auto-dialer to make calls to wireless phones, there is no explicit measure outlawing SMS spam, yet.
Measures in the U.S. House of Representatives and Senate were introduced this year to rectify that. The m-SPAM Act, introduced by Sens. Olympia Snowe, a Maine Republican, and Bill Nelson, a Democrat from Florida, would expand the regulatory authority of the Federal Communications Commission and the FTC to intervene against SMS spammers and would explicitly bar marketers from sending text messages to any mobile number in the national Do Not Call registry.
A similar measure was introduced by Rep. Phil Gingrey, a Georgia Democrat, in March after his antispam effort last year failed.
How big a problem is this?
While people in the U.S. might receive two SMS spam messages a year, things are worse in other countries like Europe where one a week is typical; India where people receive as many as two per day; and China where it's more like five to 10 each day, according to Ferris Research.
Last year, Ferris Research estimated that wireless users in the U.S. received more than 1.1 billion spam text messages in 2007, up 38 percent from 2006.
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