I saw this headline this morning in The Star (read the article on IOL):
An sms and social network frenzy saved a Joburg man who was trapped in his car boot after being hijacked at the weekend.
What a terrific story and a great ending for the poor guy who was hijacked. I disagree that Twitter is a truly useful social network for personal sharing but when it comes to social signalling, Twitter is possibly the best tool available. This story just demonstrates its effectiveness.