[For New Zealand visitors, the quick solution is probably to use geographical searching, although sometimes Twitter cannot keep up with the work that it needs to do: (eqnz near:"new zealand"). Or use a filter you'll have to keep updating.]
There was another earthquake in Christchurch today, strong enough that I felt long period shaking four hours' drive away in Dunedin, which made me very worried about my many friends up the coast. I did what everyone does in these situations, popped #eqnz into Twitter, and found myself connected to the stream of reports and rumours.
Initially I was a little concerned as most of the reports were from outside Christchurch, with few from the city itself, but this cleared up as networks, phones and power quickly came back to life. For about twenty minutes I, and the world, had a great source of news on the happenings, and a great sense of relief that, basically, everything was fine.
Then, just as we wondered why this thing wasn't trending, even in New Zealand, the #eqnz tag finally got noticed by Twitter and the inevitable happened.
Rapidly created accounts with nonsense but early in the alphabet names flooded the tag, and those for popular movies and memes, with links to modestly disgusting porn and SEO sites. Fine, try to scam some movie or the latest tween obsession, but an Earthquake? Please.
Anyway, these people, we already know, have no compunction about their activities, and merrily waste bits and oxygen as they usually waste our time, but when they instead clobber a useful utility in a time of crisis, well, that utility is less useful.
And this is where this is Twitter's problem. Me, and a hoard of well-meaning Kiwis did our best to block these bloodsucking scum from the feed, but, and this amazes me, it takes four clicks to get from the search feed to finally reporting an account, and then, of course, it's too late anyway, as the spammer's gone and made ten or twenty more.
Twitter could do something useful here. First, they can fix the reporting for spam by adding a single big button to press, right there in with the search results.
Second, while people found they could get better news by using geographical filtering (eqnz near:"new zealand"), this still hides a lot of useful information. Twitter need to provide a way to search based on the reputation and activity of users, allowing and making it easy to only see tweets from the trusted, from accounts that have existed for more than three minutes, and which have activity profiles consistent with their belonging to real people.
If Twitter can fix that, they might survive, but if they cannot, the whole service is going down the drain...
Update: It gets much better once the tag isn't trending globally. I really hope twitter can sort something out for the next big distaster.