Twitter has launched an alert service in public beta for government bodies, public services and NGOs in the US to use Twitter to make people aware of emergency situations.
The service comes with a special composer for certified organisations to create their message, with each organisation given a short URL where they can login and get people to follow.
The push notifications and SMS alerts are designed to work whether people use Twitter's apps and the mobile web. The messages can be retweeted, favourited and replied to but are designed to stand out from other tweets.
