We just saw Twitter broaden its use of push notifications for tweets it thinks you might find interesting, and the social network is now also expanding their use for a more serious matter. The company has just announced a new Twitter Alerts feature, which it says will deliver "accurate information from credible organizations" during an emergency or natural disaster. To ensure you don't miss them, those alerts will be delivered via SMS in addition to a push notification on Android or iOS, and you won't be getting notifications from just anyone who wants to send them. At launch, only a hundred odd NGOs and governmental agencies in the U.S., Japan and Korea are able to send the alerts, although Twitter says it will be expanding that to include organizations in other countries. You can sign up to receive the alerts by going to an organization's Alerts setup page; just add "/alerts" at the end of its Twitter URL, or find it on Twitter's list of participating organizations.