TwiTerra is built on the social messaging service Twitter, which allows users to broadcast 140-character status updates for interested friends, family, coworkers and strangers. It is common for Twitter users to re-broadcast the ‘tweets’ of others, and these ‘retweets’ repeat an idea or pass on a message from a person that the initial user is following to all of the people who are following that person, with attribution given to the original author.

TwiTerra uses the Twitter API and the third-party Twittervision API to build data models of geo-located retweet trees, showing how an idea is initiated with an original tweet and branches out as other users re-broadcast it. This information is gathered constantly and stored in a database, which is later visualized on a globe using a set of open-source Java libraries created by NASA.

Retweets are broadcast to audiences that are different from the audience of the original tweet, and this non-discriminatory message forwarding can expose incidental recipients to content that they might not have otherwise seen. Thus Twitter can serve to break people out of the echo chamber of these otherwise homophilous social networks, and TwiTerra visualizes these liberations in the context of both each other and of the planet as a whole.