Who are the major providers for sending mass text messages? There have to be some--I know universities and local governments have SMS warning systems set up. My cell phone carrier also sends me promotional texts. Also has anybody out there used such a service? How do they typically charge? Are you able to track analytics? What are the drawbacks with the technology? If you have tens of thousands of subscribers, will it be slow? I'm looking into a business model that may use it and would appreciate any insights.