The summer riots provided an unexpected boost for digital billboards. Police in Birmingham and Manchester hired vans bearing giant digital screens showing CCTV images of people who had run amok in the cities' shopping centres. Parking in the affected areas, the so-called 'digivans' were used to encourage members of the public to tell the police if they recognised any of the displayed faces.
The initiative was supported by an online 'rogues' gallery', so it is not clear whether the main catalyst to identification was the web or the digivans.
However, Ian Taylor, founder of digivan operator Media Displays, which worked with police in Birmingham, claims three or four arrests were made after people identified alleged looters on the big screens. 'One guy saw himself on a screen and handed himself in to the police,' he says, adding that the campaign created 'significant public reassurance that the police were fighting back - the retailers were delighted'.
Picking up pace
A more general appraisal of the sector reveals that digital outdoor is taking off after a slow start. Following CBS Outdoor's installation of the first digital escalator panels at Tottenham Court Road station in 2005, the medium struggled to progress beyond the London Underground.
However, in the past year, the medium has expanded somewhat, with brand owners and agencies embarking on interactive campaigns that combine social media and digital outdoor.
'It definitely started slowly and media owners overpromised on the medium - there was a lot of hype,' says Neil Morris, founder of digital creative agency Grand Visual. 'In the past 18 months, we have observed a real change in the way the medium is being used. The promise is being fulfilled.'
Many of the medium's early executions involved unimaginative variations of TV ads. These may have been eye-catching, but were a far cry from the agile, lively and connected campaigns that advertisers were hoping for. This all changed during last year's football World Cup, when Nike streamed live comments about England games to outdoor screens. The work seems to have inspired other brands, which have since decided to dip their toes in the water.
There are now a dozen or so case studies showing how brands have used digital outdoor as part of interactive campaigns that also involve dedicated websites and social media (see boxes).
This willingness of marketers to experiment has apparently translated into an increased spend on out-of-home digital media. In the second quarter of this year, digital revenues grew by 10% year on year to £29.8m, according to Outdoor Media Centre. This is good news for the out-of-home sector because those digital revenues accounted for more than 14% of outdoor spend.
However, advertisers still need persuading that digital outdoor has sufficient reach to make national campaigns worthwhile. Annerie Hughes, head of marketing at Virgin Trains, says the interactive element will be essential to the success of the medium, which, she argues, is being held back by scant provision of decent locations.
'Our ability to benefit from digital campaigns is hampered by the lack of good-quality sites - those that allow for a decent moving image - outside London,' she says. 'There are a few key sites in other cities, but for us to fully reap the benefit of spending money on creative, media owners need to install more nationwide digital packages.'
Hughes cites the Liverpool Media Wall - the biggest full-motion digital screen in Europe, run by Ocean Outdoor - as an installation that works well for her brand.
Opportunities to see
The operators of outdoor sites defend their record of creating national coverage. David McEvoy, marketing director at billboard operator JCDecaux, says digital screens have created a powerful channel for outdoor campaigns, although proving their effectiveness has been difficult.
'The one thing we are still not getting across to media planners is the scale of the audience we get,' he explains. 'Someone will buy (space on) a website delivering thousands of hits, but we get 350,000 "hits" a day at Waterloo Station. This is a world of big numbers.'
JCDecaux has 1200 digital panels across the UK at roadsides, in shopping centres and within railway stations and airports. The company claims that these panels 'deliver 300m impacts every two weeks', reaching a potential 31% of the population. It also states that digital screens can be twice as likely to get noticed than static posters and hold people's attention for longer.
The greatest concentration of digital screens is on the London Underground, where CBS Outdoor operates panels in 28 central Tube stations.
As ever, return on investment is a key consideration. Carolyn Nugent, head of digital at outdoor media buying agency Kinetic, believes much more work is needed to assess the ROI of the medium, which she describes as 'still in its infancy'.
Mindshare group account director Lucy Catchpole says proving ROI is tough for both forms of outdoor advertising, whether it be digital or print. She cites Lynx's outdoor campaign 'Fallen angels', which, with the help of augmented reality and a camera, projected passers-by onto a screen standing next to an 'angelic' woman.
A film for the campaign, which also takes the form of a video game, has attracted almost 1m hits on YouTube. 'Digital outdoor definitely works and drives people to other media,' says Catchpole. She adds that although static poster panels are cheaper to rent than digital screens, the extra cost of the latter is no great deterrent for the biggest advertisers when the priorities are reach and engagement.
However, Clear Channel chief executive Matthew Dearden is sceptical about the hype surrounding digital billboards, which account for a small proportion of his company's poster sites.
'What exists today is great for some clients, but is not right for all of them,' he says. 'A lot of noise was made about relatively little when (outdoor) digital (panels) were launched. I want to be careful not to do that.'
Media Displays' Taylor predicts a busy 2012 as local authorities hire his digivans to screen Olympic events in public places; there will be opportunities here for London 2012's sponsors, too.
In the longer term, moves are being made to connect outdoor screens with mobile phones through technology such as QR codes and near-field communication. A recent outdoor campaign for the film X-Men: First Class used a chip behind a poster so passers-by could view the trailer for it on their phones.
Advertisers, then, are keen to experiment with interactive campaigns using digital outdoor. It just needs to prove itself.
Foster's Gold launched in the UK this month, supported by an interactive campaign hosted on digital screens at 10 bus shelters.
Visitors to the shelters are urged by the screens to select their preferred 'smart, casual' outfit from a range of options. A camera in the screen takes a picture of the participant, who is then presented 'wearing' the chosen attire - and holding a bottle of Gold - alongside brand characters Brad and Dan.
Pictures are uploaded to Foster's Facebook page, from where they can be shared with friends. The work was created by Adam & Eve.
Yell.com recently ran a digital outdoor campaign showcasing its local business information and reviews service. Screens in railway stations gave information about destinations such as 'Heading to Southend-on-Sea? Try: Southchurch Park Cafe', followed by a customer review.
The campaign, created by Rapier, ran on JCDecaux's Transvision screens. It led to a 600% increase in searches for reviews on Yell.com, according to the client.
THE HUFFINGTON POST
To promote The Huffington Post's UK launch in July, members of the public were urged to tweet their views on current events, with the comments sent live to JCDecaux's Transvision screens in railway stations. Mock newspaper sellers at the stations were employed to shout 'Blog all about it'.
The tweets were displayed under provocative calls for participation.
The activity was created by MBA.
Car-rental service Europcar launched a live digital outdoor campaign in June promoting FreeDeliver, a vehicle delivery and collection service, which the company claims could save 'an hour in your day'.
In reference to this freed-up hour, Twitter users could answer the question 'What would you do?'. Their responses, using the hashtag '#myextrahour', were streamed to roadside screens and sites in railway stations.
Europcar says the work, created by Ogilvy & Mather, boosted web visits by 32% year on year, as well as prompting 120,000 hits on YouTube and more than 500 mentions on Twitter.