To end reply STOP.” Annoyed, I typed “STOP” and hit send. “Six months ago, when I would tell people I work for an anti-spam company and work on mobile spam, they’d all wonder, ‘What’s mobile spam? The past three years, however, have brought a proliferation of cheap, prepaid cellphone plans with unlimited text messaging. In 2009, Americans received some 2.2 billion text messages that they identified as spam, by the estimate of Richi Jennings, an independent market analyst. But even that figure doesn’t capture the biggest boom, which has come in just the past few months, according to Cloudmark, a San Francisco-based firm that provides messaging security for major wireless carriers.Clicking the button switches its label to 'Awaiting Bang' but will not notify them of your interest.