Envy Magazine Houston (soon to be launched in Dallas too) - uses a qtags text-in program to build an opt-in group for news alerts. They publish the call-to-action 'text "envymag" to 78247 (QTAGS) to get on the VIP list'.
And then they push alerts (e.g. party updates / where DJ AM is appearing, etc) to the live opt-in group. Because their audience is vest in the brand and truly does want to know - they have very low opt-out activity.
This would work great for any advertiser with a vested audience. We're starting it Sept 17th with Communities in Schools Houston. Kicking it off at their annual fund-raiser - and asking people to text 'helpkids' to stay in the know. Now CISH will be able to communicate with these folks long AFTER the event and solicit their help for future programs; like money for school supplies, and other programs to support the kids.