The Virginia Tech shooting was the significant event that pushed not only schools and universities to get phone notification systems, but energized the entire industry. At one point there were over 87 companies offering phone notification systems of one type or another. Already that number has dwindled to around 37.
The major players are still around and offering services, but the new IPAWS and CMAS programs that are just coming on line will enable emergency managers and other first responder agencies to use "unregistered" phones and alert people by geographical area--in the case of cell phones anyway. For more on the two Federal programs you should be following the blog Alerts and Notifications by Rick Wimberly and Lorin Bristow.
The recent Waldo Canyon Fire exposed several vulnerabilities to the existing warning system. See 21K Never Received Waldo Canyon Evacuation Call There are limitations to what the systems can do. People have to be registered and the phone system needs to be available and not overloaded with calls. There is a necessary interface between the phone system and the commercial phone systems providers. In instances where there are problems the inevitable finger pointing between the two providers can be expected.
Then there is the social piece of it. People, even after being warned, must take action in a timely manner. One Colorado emergency manager told me that all the people who died in the Waldo Canyon Fire did get a physical evacuation notice, yet still were taking time to load up possessions before evacuating.
As many a technology company has found, the pace of change can rapidly make your "solution" obsolete and not necessary. Emergency managers cannot think that what has worked for the last five-ten years will work in the future. It is one argument for purchasing hosted applications so that you don't have sunk costs in hardware and software that soon becomes outdated.
I fully expect that telecommunications companies will latch onto the opportunity to use the alert and warning capabilities of their systems as a competitive advantage.
Marty Pastula passed along the link to the Colorado story.