gathered from all sources, compiled, and manually evaluated. The validity of evidence was assessed to include the content of the data, as well as the reputation of its source; for example, solitary tweets without detail sent from new Twitter accounts with no followers were discounted, while those from established users with geo-tagged photographs (attached) were given a higher-reliability assessment.

The cyberspace search approach also used a Twitter-capture system to store and search tweets about the Challenge offline, as well as a custom Web crawler set to record data from the publicly accessible parts of Web sites of competing teams. Since analysis of the data captured by the crawler required more time, it could have been more helpful if the Challenge continued longer than the one day the balloons were deployed. However, the Twitter-capture system turned out to be more helpful, as it revealed locations from users allowing their smartphones to embed geo-data with their tweets. Unlike manually geotagging photos, falsifying data was more difficult through the current set of tools and therefore deemed more reliable.

Several reports were confirmed as false through a combination of photograph analysis and secondary confirmation by dispatched observers. Observers from the pre-event recruiting effort were used where possible (such as detecting the fabricated photo in Figure 5 of the balloon over Albany, NY). Where no pre-recruited observer was available, the command staff and cyberspace search staff called and recruited observers from the iSchools Caucus member organizations, family, and friends known to be near unconfirmed sightings. This technique was used to confirm the valid location in Portland, OR, and disqualify the fabricated image of Providence, RI, in Figure 4, right, and the non-DARPA balloon over Royal Oak, MI, in Figure 4, center.

In one case, a competing team un-
intentionally leaked details on its Web
site of an accurate balloon sighting in
Scottsdale, AZ. An attempt to cover up
the leak and misdirect others to think
the balloon report was in another state
created an inconsistency in the story
posted with the photograph. To iden-
tify the true location of the sighting,
the iSchools team triangulated infor-
mation across many social networking
sites. Following geographical clues in
the original posting, 3, 10 the team con-
firmed the true identity and likely home
location of the original poster. The
location of the balloon was then con-
firmed by matching the original text
description (in the park near the post-
er’s house) and comparing the poster’s
photograph of the balloon with photo-
graphs of the park on Panoramio (see
Figure 6). This illustrates the poten-
tial of piecing together bits of publicly
available information across disparate
sources in a timely way to solve a piece
of the puzzle.

Reflections

This experience generated insights at several levels. Diffusion of the Challenge itself demonstrated the complementary roles of traditional mass media and social media. Comparing the strategies of the three teams at the CSCW panel yielded interesting contrasts and implications for how to validate submitted information, adding to DARPA’s reflection across all participating teams.

Diffusion of the Challenge through mass media and social media channels provided a good comparison of the relative roles of traditional and social media methods in network mobilization. The initial announcement at the “40th Anniversary of the Internet” event in October and some widely circulated blog posts (at mssv.net and Slashdot) generated a steady trickle of traffic to the DARPA Web site, averaging about 1,000 hits per day. Initial expectations that the diffusion of the Challenge would progress virally were not realized until the final week before balloon launch. A steep increase in Web-site hits corresponded with the appearance of a story in the New York Times, November 30, 2009, with Web-site traffic increasing to an average of 20,000 hits a day in the last week before the balloons were launched.

Diffusion of the Challenge (itself an experiment in social media) showed how traditional mass media and social media channels are complementary. At least for this target audience and in this time frame, it took a combination of mass media and social media to effectively disseminate information

approaches used by three teams—mit, GtRi, and ischools—in the Challenge.

mit
team motivation
Extrinsic financial
incentive

GtRi

Intrinsic altruism
direct personal
verification

ischools

none

Balloon Validation social media usage mass media usage

human analysis
of submitted
information
Form team network,
Attract balloon
sightings
Publicity on launch
day
may have attracted
balloon sightings
Attract balloon
sightings
Publicity before
launch
may have added to
team and attracted
balloon sightings
Mined for published
information
none
human and
machine analysis
of submitted and
public information
APRIL 2011 | vOL. 54 | nO. 4 | CommuniCations oF the aCm 83