Sending text messages to phone numbers of owners who have not opted-in to your SMS campaign is an illegal practice. It is a violation of federal law under the TCPA, and it can result in costly lawsuits. Consumers can sue you for sending them unsolicited messages, and they can claim between $500 and $1,500 for every unwanted text message that you have send to them.
In Europe the first cross-carrier SMS shortcode campaign was run by Txtbomb in 2001 for an Island Records release, In North America it was the Labatt Brewing Company in 2002. Over the past few years mobile short codes have been increasingly popular as a new channel to communicate to the mobile consumer. Brands have begun to treat the mobile short code as a mobile domain name allowing the consumer to text message the brand at an event, in store and off any traditional media.