One-Way-Mirror Society: Introduction – What is digital signage and why care about its privacy implications?

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The digital signage networks this report addresses are bi-directional. These networks give information to viewers while they capture information from viewers and send it back to a home base. In the digital signage industry, the new technologies are often compared to the interactive signs from the movie Minority Report. [1] In the movie, large-screen video billboards recognized individual consumers and delivered personalized advertisements to each person. The movie version of the digital signs and billboards relied on an iris scan to customize the ads. Today’s modern digital signs rely on advanced video analytics and sophisticated cameras and sensors.

Digital signs typically output video, but that is only half of what they do. They can also be outfitted with hidden facial recognition technology, pinhole cameras, and even infrared cameras. As people walk by these signs, these signs capture consumer images, analyze them, and report the data back to their operators and tell those operators a great deal. The screens are typically networked to a central location and can be controlled remotely in real-time.

Digital signage is becoming ubiquitous while remaining secretive. The vast majority of people walking in stores, near elevators and in other public and private spaces have no idea that the innocent-looking flat screen TVs playing videos may be capturing their images and then dissecting and analyzing them for marketing purposes or personalizing and targeting ads to them. Most people do not know that the advertisements they see may be different than those displayed to another person in the store because of their gender or age.

Digital signage raises a host of policy questions. How long will it take before the signs support differential pricing based on sex, race, and other demographic characteristics? Are the signs in stores recording children under 13? Who is able to access the footage: police, private litigants, tax enforcers? What disclosure is given to consumers that this is happening? What is the proper role of consent in data collection and use? Sadly, there are more questions than answers.

Digital signage is a privacy Chernobyl just waiting to happen, unless something is done quickly, and proactively. When customers realize how pervasive and how invasive this digital sign surveillance is, they will not like what they learn. Controls need to be put in place now, before this technology runs amok and becomes an entrenched problem that is too systemic to root out.

Society has not adequately confronted the conflicts that arise over privacy in public spaces. Individuals give up some privacy when in public, but that does not automatically mean that tracking everyone everywhere is unobjectionable. The ability of modern technology to watch and record people constantly while in public places enormous pressure on the old notion that there is no privacy in public. Unrestrained surveillance and collection of personal data through digital signage force us to confront the conflicts sooner than later. [2]

Defining digital signage

POPAI (Point of Purchase Advertising International), [3] a large, well-established
global organization for marketing at retail and the digital signage industry, defines digital signage as:

“A network of digital displays that are centrally managed and addressable for targeted information, entertainment, merchandising and advertising. Synonyms: dynamic signage, digital signs, electronic signage, digital media advertising, digital signage network, in-store TV network, captive audience network, narrowcasting network, out-of-home media network, digital media network, advertising network.”[4]

Bill Gerba, a respected digital signage expert and CEO of WireSpring, a digital signage company, has offered this definition of digital signage:

“Any kind of electronic display (such as a TV, computer monitor, or flat screen) that can be remotely controlled over a computer network (like the Internet) and is placed into a venue to show targeted information, content and advertisements.”[5]

Although digital signage is not new by any means, in 2006 it reached a new maturity due to the introduction of surveillance technologies that could capture, measure, and analyze how people were responding to the signs, and even the demographic profile those responding to the signs. By 2008, start- up companies had introduced competing analytical products based on these ideas for retailers, hotels, colleges, and others interested in signs that both deliver and capture video. Digital sign networks currently boast a high level of sophistication, and the technology is continuing to mature fairly rapidly. [6]

An Intel Solution Brief about digital signage stated:

Consumers watching advertisements in stores, airports or just about anywhere probably don’t realize that some digital signage systems are helping advertisers gauge their interest. Equipped with cameras and anonymous facial recognition software, these systems detect personal features and determine whether consumers are paying attention to the display, just glancing at it or ignoring it completely.

The brief also stated:

With this capability, called “anonymous video analytics,” advertisers can also target specific demographic groups by displaying ads that are compelling to the viewing audience. For example, the systems can dynamically change their content if the audience is male, female, a senior, or a family. [7]

The possibilities of the technology are mesmerizing, and it is already in use today. Companies have already been running campaigns using the capacities of the advanced surveillance analytics of digital signage to gather information about those interacting or passing by the signage and to tightly tailor ads to individuals.

Modern digital signage in action: the Castrol digital billboards

On September 21, 2009, Castrol, a large oil company headquartered in the UK, [8] launched a highly personalized digital signage campaign in London. The campaign was “Right oil, right car.” The idea was that Castrol would use advanced digital signage technologies to capture car information and them make custom oil recommendations to each passing car via a roadside digital billboard. To do this, cameras were positioned just before the billboards to capture the license plates of approaching cars. The cars’ license plates were then matched in real time to the make and model of the car via the company’s access to the UK Government’s Driver and Vehicle Licensing Agency database. [9] (The DVLA database is the database of car registrant information in the similar to the state-level Division of Motor Vehicles and its databases in the U.S.)

Within 2 seconds, as the drivers passed by the billboard, the billboard displayed the car’s registration and a personalized oil recommendation. Each personalized ad was displayed for 7.5 seconds. (Figure 1).

Figure 1
The Castrol personalized digital sign campaign in London. As cars approached the digital billboard, images of motorists’ license plates were captured, matched to a database, then the billboard displayed an ad tailored to that make and model of car.

The Castrol campaign itself only lasted four days – the UK’s DVLA launched an immediate investigation into how the car registrations of millions of drivers were sold for use by a large multinational oil firm. UK news reports on the issue revealed that Castrol used a third-party company to obtain the data from the database. [10]

The Castrol campaign is illustrative of the capabilities of the technology, and some of the privacy issues inherent in its use.

The digital signage industry is not unaware of privacy and other consequences of the technology, and industry has begun to think about some of these issues. An industry-crafted Recommended Code of Conduct for Consumer Tracking Methods (See Appendix A) describes some of the digital signage technologies that are privacy-invasive and seeks to encourage avoidance of some of the worst practices. But the industry by and large is not pressing for strong privacy protections in digital signage networks.

Digital Signage by the Numbers

Digital signage is not new, but it is considered to be the most promising newcomer in the digital advertising ecosystem. Any business or institution that can hang a high-definition screen and use it to track customers is a potential candidate for digital signage. Gas stations, [11] sports stadiums, [12] subway cars, [13] elevators, [14] bars, [15] movie theatres, [16] airports, [17] grocery stores, [18] retail stores, [19] restaurants, [20] college campuses, [21] museums, [22] casinos, [23] malls, [24] hotels, [25] and hospitals [26] are among commonly seenvenues for digital signs and digital sign networks. [27]

The full maturation of digital signage as a viable and growing medium for marketing began in earnest around 2005-06. A Forrester Research report captured the beginning of the cycle when it reported in 2006 that by 2011, 90 percent of U.S. retailers would have implemented some form of “customer- facing, in-store digital media network.” [28] In 2008, POPAI blogger Jeff Dickey wrote

Digital signage is on the verge of becoming a truly mass media that, within a decade, should reach more people on a daily basis than traditional television, radio or newspapers. It is not television and it is not the Internet. It is a little of both and a lot of neither. [29]

While the 90 percent figure from 2006 was likely too optimistic, [30] the overall trajectory was correct. In-store and out of home digital networks have indeed taken hold, and the upward trend is strong worldwide. While there is no available study showing the degree of market penetration, by looking at individual businesses and vendors it is possible to get a sense for the overall size and scope of the industry.

In the U.S., Arbitron research indicates that about 155 million people have seen digital “out of home” displays. [31] (Digital out of home, or DOOH, is a term of art in the digital signage industry that generally refers to signage in places other than a home). A UK-based media company, SymonDacon, has placed 20,000 digital signage installations worldwide. [32] Scala, a company headquartered in near Philadelphia in the U.S., states that its global digital signage reach is in excessive of 300,000 screens worldwide. [33] In 100 U.S. malls, a company called Adspace creates campaigns on a network of 1,400 digital screens. [34] TransitTV operates more than 8,400 screens in buses and trains worldwide. [35] Quividi, a company that measures audience response to digital signs, states that the number of consumers that have looked at digital signs that contain its proprietary technology is 120 million people. [36]

Digital signage revenue is forecast to grow at a compound rate of about 20 percent to 2016. [37] The basis for the forecast rests in a combination of research showing that a preponderance of consumers’ purchasing decisions – especially brand decisions – are made after they are physically in a store or retail location. “[C]onsumers make about 70 percent of their brand decisions once they are in-store, opening a window for grocers and manufacturers to target shoppers and they make their way through the aisles.” [38]





[1] For more information, see IMDb Minority Report overview page <>.

[2] See, e.g., Christopher Slobogin, Camera Surveillance of Public Places and the Right to Anonymity, 72 Mississippi Law Journal 213, 233 (2002).

[3] Point of Purchase Advertising International (POPAI) <>. “POPAI is the only global, non-profit trade association dedicated to the advancement of the marketing at retail advertising medium. Founded in 1936, POPAI is the oldest association representing marketing at retail with 20 chapters worldwide, with headquarters in Metropolitan Washington DC, and representing over 1,700 member companies internationally.”

[4] Point of Purchase Advertising International (POPAI) <>.

[5] Bill Gerba, POPAI introduces Digital Signage Standards, October 28, 2005. < Signage_Standards-250.html >.

[6] In addition to the current use of cameras in screens, new technology is emerging that will further mature the industry. See for example, Siggraph Asia 2009 e-Tech Prototype, the BiDi Screen. This LCD screen is bi-directional and allows for 3-D interaction using hand gestures. Photo-diodes are used as sensors. See <>.

[7] Reaching the Right Audience: Intel technologies in digital signage systems help maximize advertising messaging and return on investment. Intel Digital Signage Solution Brief, <>.

[8] Castrol, <>.

[9] UK Department for Transport, Driver Vehicle and Licensing Agency. <>. See also DVLA information regarding data release <>.

[10] Christopher Leake, Drivers’ details sold by DVLA are used in bizarre roadside adverts for Castrol, The Daily Mail, Sept. 27, 2009. < adverts-Castrol.html>.

[11] See Gas Station TV, <>. See also <>.

[12] Stephen Lawson, Cisco plans networked screens at Yankee Stadium, TechWorld, November 13, 2008. <>.

[13] See TransitTV <>. See also < >.

[14] See The Elevator Channel, <>.

[15] See TapTV <>.

[16]See <>.

[17] See AirMedia <>.

See also: For The World’s Largest Digital Signage Networks— Look at China, <>.

[18] The Marketplace Station Introduces In-Store Digital Stations at Whole Foods Market to help Marketers and Consumers, November 17th, 2008. <>.

[19] See discussions of WalMart’s digital signage network; ex.: Bill Gerba, Walmart’s Cost-Supplement Initiative: Retailer Becomes Ad Agency, July 22, 2009. < nt_Initiative__Retailer_Becomes_Ad_Agency-731.html >. See also Jane Goodwin, WalMart Digital Signage Celebrated Earth Month Last Year, March 20, 2009. < celebrated-earth-month-last-year/>.

[20] First All digital restaurant sets new standards for QSR, POPAI, Sept. 25, 2009. <>. 21 Digital Signage to Make Campus Safer, Greener. Univeristy of California Press Release, October 22,2009.


[22] OpenEye Develops Digital Wayfinding System for the National Museum of Natural History at the Smithsonian Institution in Washington D.C. <>.

[23] Cisco Announces Interactive Digital Signage Pilot with Harrah’s, Jan. 11, 2009. <>. See also Cisco Digital Signage, <>. Harrah’s Casinos is piloting a large digital sign project. The Harrah’s signs could be integrated with back-end business analytics systems and databases, which would allow the casino to offer deals based on individual consumers’interests

[24] Southcentre Mall Deploys Digital Signage Powered By Omnivex Software, Dec. 17, 2009. < uthcentre-Mall-Deploys-Digital-Signage-Powered-By-Omnivex-Software/Default.aspx>.

[25] Bill Yackey, Four Winds outfits Royal Caribbean’s Oasis of the Seas with digital signage, Dec. 21 2009. <>.

[26] See Catholic Healthcare West, <>.

[27] Joab Jackson, IT Firms Promote Interactive Digital Signs at Retail Show, PC World, Jan. 14, 2010. <,186959/printable.html>.

[28] How Digital Media Transform In-Store Marketing, Forrester Research, 26 April 2006. Nikki Baird, with Carrie Johnson, Sean Meye and Brian Tesch. See also In-Store Digital Media: How to Reestablish Retail’s Role as a Mass Consumer Medium. Bill Collins, Dorothy Allan, Decision Point Media Insight.

[29] Jeff Dickey, The Evolution of a New Media, July 10, 2008. POPAI <>.

[30] It is difficult to accurately determine exact percentages of penetration. But, for example, In 2008, about 25 percent of retailers were using camera-enabled traffic counting technology, one component part of some digital signage systems. See Deena M. Amato-McCoy, Stepping it Up: Traffic-Counting Technology Improves Marketing, Sales, Chain Store Age, Vol. 84, No. 5, May 2008.

[31] Joab Jackson, IT Firms Promote Interactive Digital Signs at Retail Show, PC World, Jan. 14, 2010. <,186959/printable.html>.

[32] Symon Dacon launch AV partner program to promote intelligent digital signage, AV Magazine, January 14, 2010 < digital-signage/>. See also Symon Dacon <> and <>.

[33] See Scala, About Us, <>.

[34] Adspace launches Trend Alert messages on mall DOOH screens, Oct. 7, 2009. Digital Signage Today, < >.

[35] David Barbara, Digital out-of-home advertising on the rise in ’10, Digital Marketing Observations, November 13, 2009. The One-Way-Mirror Society, p.10

[36] “120 million people counted in the VidiCenter: the foundation of our expertise.” Quvidi home page,

[37] Digital Signage Display Revenue to Grow at 20 Percent CAGR to 2016, Digital Signage Expo, July 11, 2009. < gital-Signage-Display-Revenue-to-Grow-at-20-Percent-CAGR-to-2016/Default.aspx >.

[38] CMM’s retail TV Network Targets Southern California’s Hispanic Consumers…Digital Signs Deliver In-Store Communications to Supermarket Shoppers. April 9, 2009, < californias-hispanic-consumers-digital-signs-deliver-in-store-communications-to-supermarket-shoppers&catid=29:popai- member-news&Itemid=76>.



Roadmap: The One-Way-Mirror Society – Privacy Implications of the new Digital Signage Networks: I. Introduction: What is digital signage and why care about its privacy implications?


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