Digital Attack Map is a live data visualization of DDoS attacks around the globe, built through a collaboration between Google Ideas and Arbor Networks. The tool surfaces anonymous attack traffic data to let users explore historic trends and find reports of outages happening on a given day. In the “About” section of the website with the live data visualization, the explanation for the need to keep track of DDoS attacks is as follows:

Distributed Denial of Service (DDoS) attacks can be used to make important online information unavailable to the world. Sites covering elections are brought down to influence their outcome, media sites are attacked to censor stories, and businesses are taken offline by competitors looking for a leg up. Protecting access to information is important for the Internet and important for free expression.

Find out more by reading the FAQ on the site http://www.digitalattackmap.com/.