It is a bit difficult to take any article seriously that claims in the title that "this technology will change your life." But Twitter, a strange cross between blogging and text messaging, may "a href="http://www.macworld.com/article/136443/2008/10/twitter.html">finally be growing up. Twitter may actually have some real value with respect to public safety, because you can have lots of people subscribed to a Twitter feed that can then quickly send a message to a lot of cellphones all at once. Twitter may also have some uses as an internal messaging systems for businesses and organizations, both for some kinds of routine messages ("the staff meeting starts in 5 minutes") and non-routine messages ("fire in the supply room, evacuate immediately).
Long term, it is hard to guess just how many different communications channels we A) want, and B) can manage. Most of us already suffer from email fatigue. It has taken nearly one hundred years for the automobile to evolve into the trouble-free, powerful transportation systems we take for granted today, and they are still changing and improving. We are barely out of the Model T era of computer and communications technology.