There was a fashion some years ago in Australia, and I presume elsewhere, for what was called “Neighbourhood Watch”. Various elements to it, but essentially the idea was that people in a community kept a lookout for each other. Might note for example if there were strangers entering a house of people known to be on holidays. Might hear suspicious noises and notify police. Might check on why the old lady down the road hadn’t collected her milk from the front step that morning. Might report strange cars with unknown occupants parked in a back street late at night. And so on.

Not a bad idea eh, aiming to change a suburb or city block from a collection of individual fortress dwellings where old people can die in their homes unnoticed, houses can be robbed with impunity when owners away, police investigating crime met with a complete lack of eyewitnesses, to a community where people watch out for each other. Oh, sure, some room for stickybeaking, nosy neighbours, troublemakers, police timewasters, privacy intrusion, but on the whole a really positive thing. Back to the way things would have been say 100 years ago and previously.

Seems to me that, on a much larger, indeed planetary scale, and on a much more ambitious idea of content, Twitter is the new universal neighbourhood Watch, where the Neighbourhood is the Earth itself, and the community is all 7 billion of us.

On a direct level twitter is providing very rapid notice of events like earthquakes or severe storms or fires or shooting rampages, tweets flashing out within seconds, far quicker than any traditional news. And it provides a billboard for community events, plays, charity shows, lost dogs, sports results, and so on.

But it is also providing a superb venue for passing information around quickly, linking to newspaper articles, political speeches, noting media mistakes. It provides opportunity for eyewitness accounts of revolutions, wars, invasions, massacres to flash around the world, beyond the scope of a dictator to prevent them. And you can find notices about climate change, damage to ecosystems, threatened species.

There is really no limit to the information exchange that is now happening. Each of us can act as an observer, a good citizen (though, just as in neighbourhood watch, there are some bad twittercitzens), picking up pieces of information here and there and adding them to all the other pieces collected by others, in other towns, in other countries.

The neighbourhood is the planet, and we all need to watch out for each other in these dangerous times.

Think globally, tweet locally.