Detailed reports of the incident show Meetkumar Hiteshbhai Desai set up a web page that reused a snippet of code that would interact with the browser on a smartphone device. He claims that his intention was to get the victim to click a link and then display an annoying pop-up message on the phone. The program would then dial 911 and loop once the call terminated, therefore making another call to 911.
Apparently the cycle was difficult to break out of, and people had to shut off their phone or remove the battery. With more than 1,800 people clicking the link and simultaneously generating calls to 911, he essentially triggered a Telephony Denial of Service (TDoS) attack.
All indications point to an accidental exploit of pre-existing click-to-dial functionality, something very common in today's environment.
To invent, you need a good imagination and a pile of junk. -- Thomas Edison