Nightwatch armbands? Hopefully not yet. In addition, I cannot see how such a system would be efficient. In my opinion, it would cause more harm than it could ever prevent.
First, filtering the information would take huge resources. Who on Earth will reliably separate paranoid worries, malicious (possibly political) harrassment and occasional real concerns?
Legions of government bureaucrats. The same kind of bureaucreats who fail to notice advance signs of most harmful developments, including but never limited to terrorist threats.
If govenrments can ignore real concerns, behave irresponsibly despite alerts from credible scientists, economists and their own analysts, how could thousands of "concerned informants" yield anything useful?
Besides, should a government really ask civilians to spy on each other? Create a framework to make it easier? It sure provides a new tool for prank threats, malicious disruption and possibly... suppression of political dissent.
Furthermore, it may encroach on privacy. Rest assured, this will not worry terrorists. Their preferred regimes have no privacy. Should they have their way, citizens would be government property, instead of governments serving their people.
Terrorists will also learn to protect their data, just as countless intelligence agencies do. Cryptography and steganography are currently well ahead of content detection and cryptoanalysis. No amount of spying will help against clever diguise and strong codes.
Only removing the reasons which cause conflict (terrorism included) and repairing societies can increase long-term security. Therefore I would deem this project short-sighted and duboius, agreeing with its critics. This may be another instance of trading liberty for securiy.
