CYBERSPACE — Anyone who didn’t see it coming hasn’t been paying attention: Mobile spam is beginning to reach epic proportions, and the outlook isn’t pretty.Every day, more than 1 billion text messages are sent to and from mobile phones in the U.S. In 2006, 800 million U.S. text messages were mobile spam. Last year, that figure climbed to about 1.1 billion. In 2008, it’s expected to reach 1.5 billion, according to market research firm Ferris Research.

Others estimate the onslaught is much more pervasive. Verizon Wireless, for example, claims to block more than 200 million unsolicited text messages every month. That’s 2.4 billion spam texts a year at only one company, and it’s not even the largest in the country.

Consumers are outraged. A survey conducted by Seattle-based M:Metrics found 28-percent of people who received text-message ads had not consented to receive them, and for good reason: Not only are spam text messages more annoying than spam emails because they seem to embody a more personal invasion of privacy, but they’re also more costly. Recipients aren’t charged by the piece for email spam; they are, however, charged by the message for spam sent to their phones.

Typically, according to consumers, text spam is advertising. Consumers have reported receiving solicitations for everything from ringtones to horoscopes, sports scores, and porn. Although cellular companies are employing increasingly sophisticated measures to block known mobile spammers, they can’t catch everything: Sometimes mobile spam, like email spam, seems to come from the subscriber himself or herself, and those messages are impossible for phone companies to block. And the legality of blocking text messages from political parties and charitable organizations is in a decidedly gray area. Although unsolicited mobile email was banned by law in 2005, not even the federal “do-not-call” registry is allowed to protect landline subscribers from so-called “charitable” and “public interest” organizations.

Of more concern recently is a new breed of scam. Called “smishing,” it’s the mobile equivalent of phishing. It’s just as malicious, but often it’s more difficult to detect. Consumers frequently authorize their banks, PayPal, eBay, and other e-commerce providers to message them about important matters, and smishers have discovered ways to mimic those messages convincingly. Because people don’t expect the cell phones to be under assault like their email inboxes are, smishers often are successful at weaseling personal details, account numbers, and passwords out of even sophisticated users.

How do the miscreants get people’s mobile phone numbers in the first place? Much as they obtain email addresses: They buy them, harvest them from databases, or hack into the records of companies that have permission to send messages to their customers’ cell phones. In some cases, tech-savvy mobile spammers can intercept random text messages containing important personal information, because most text messages are sent without any form of encryption.

Mobile operators are not unsympathetic to the problem. Increasingly, they’re employing sophisticated mechanisms to filter out unwanted text messages. Verizon is even taking mobile spammers to court. Last year, it sued telemarketers it said sent more than 12 million unsolicited commercial text messages to its subscribers, hitting customers with unwanted charges and bogging down Verizon’s network.

Consumers, too, are beginning to fight back. In October, an Illinois resident filed suit against Facebook for sending text messages to her phone. Her number previously had been allocated to a Facebook user who subscribed to Facebook’s mobile alert service. Another Illinois resident in 2006 sued Distributed Networks for sending unwanted messages to her mobile phone.