It's not quite the world of Minority Report just yet, but targeting commuters has moved far beyond simply using a billboard on the M4 and an ad in the Evening Standard.
Outdoor advertising remains one of the best ways to reach people on the move and it is also one of the most innovative media channels today - with new formats and technical wizardry being introduced every few months.
The quest for the visual "wow factor" and more has led to posters of all shapes and sizes, exotic lighting effects and digital screens with animated graphics. New technology has enhanced the opportunities for customer interaction, from using Bluetooth and downloading music clips to six-sheet panels that dispense sweets.
With the increasing shift to digital media, better targeting is possible with day-part and week-part advertising and dynamic copy changes becoming reality. Investment in digital formats is likely to ramp up dramatically once the London Underground contract awarded to Viacom Outdoor enters its new era.
Of course, it's not only outdoor media owners getting in on the act - podcasts and mobile-data services are providing new ways for newspapers, radio stations and websites to target commuters.
Here, we outline the four biggest ways in which advertising to commuters is evolving in front of their eyes.
Now more than ever, advertisers are after stand-out - and visual impact is one of the most effective ways to achieve that. Every sector of outdoor - from rail stations to roadside billboards and bus shelters to the buses themselves - has unique and exciting innovations to increase visual appeal.
The likes of Clear Channel and JCDecaux have a long history of creating dramatic visual displays with their bus shelters and will often add sound effects as well.
For example, Clear Channel recently ran a campaign for Andrex with puppies that turned from pink to blue using "kaleidoscope" technology that changed just the colour of the puppies and text while the background colour remained constant.
The battle for the Tube contract has been generating most of the column inches, but Viacom Outdoor has been innovating in the field of bus advertising as well. There are now 25 buses with LED screens on the side that advertisers such as Yell.com, Sony Ericsson, COI and Lastminute.com have used to target an audience of bus passengers, pedestrians and motorists.
Nicky Cheshire, sales director for the Impact and Digital divisions at Viacom Outdoor, says some of the best innovations are remarkably simple - such as the "twinkly t-sides" for the launch of Emma Thompson film Nanny McPhee, which were simply LED lights that flickered on and off. "Using a little bit of innovation we were able to create that magical quality," Cheshire explains. "We also ran another creative along the same lines for the launch of Mission Impossible 3 for UIP."
Another crucial factor in creating visual stand-out is size. Titan Outdoor, formerly Maiden Outdoor, is justifiably proud of its 17 Transvision screens on the concourse at mainline rail stations around the country - these are hard for a rail commuter to miss because of their size and prominent location next to the indicator board.
Titan also has new formats on platforms such as Spotlight, a square backlit format on commuter stations in London and the South-East, which it is using to woo fashion and beauty advertisers.
JCDecaux has been investing heavily in creating visual impact with new shapes and sizes of billboard such as the V800, which has a vertical component that can be re-angled and redecorated as anything from an aeroplane to a bottle of champagne. Dave McEvoy, group marketing director at JCDecaux, says there is an increasing trend for portrait-shaped billboards - if a billboard is 20-foot long it might be 30-foot rather than 10-foot tall, trebling the amount of advertising surface area.
The most high-profile of all is the Torch, which is the size of an 11-storey building with two large digital panels and sits on the M4, the main route for commuters from the West into London or the gateway to Heathrow Airport.
Deborah Lee, group account director for outdoor specialist Kinetic, says she is encouraged by the continued investment in outdoor. But for many brands it's more important to get coverage than to spend money on one-off specials.
"You have to weigh up the budget and the creativity of the brand - if you have a brand that isn't particularly creative or the creative work isn't right or the message isn't right, it's not worth it, whereas for a film advertiser it might be perfect," Lee says.
She adds that the Torch would be fantastic for business advertisers and the proximity to Heathrow is probably even more important than its ability to reach commuters.
The current buzz word in the media world is "engagement" and interactivity is often seen as a sure-fire route to achieve this. Outdoor media owners are full of ideas to increase audience interaction, particularly in bus shelters or train stations where commuters congregate and dwell-time is relatively high.
In September 2005, JCDecaux created a six-sheet poster that dispensed sweets to passers-by to tie in with O2's "Treats" campaign. JCDecaux has also installed interactive displays in bus shelters to promote movie launches - currently Disney's Shaggy Dog - and video games.
Clear Channel recently installed six-sheets with touchscreens at Clapham Junction and Islington in London in an expansion of the "Green Light District" campaign that started in Edinburgh last year. The touchscreen provides an interactive map showing local pubs and bars.
Mark Middlemas, managing partner at Universal McCann, says he received some amazing ideas for the launch of the Xbox 360 game console but cost was a factor.
"We played some of the games in a bus stop in France but couldn't do that in the UK because we didn't have the money," Middlemas says.
"Another problem is that it's not always easy to do a couple - you have to buy a massive package and then sprinkle the special builds among it, but some clients will shy away from that."
Titan's PromoRail division specialises in providing opportunities for advertisers to exhibit on the station concourse. Stephen Edwards, group head of Unique at Titan Outdoor, says this allows personal interaction with commuters on their way home from work. "We've been running an experiential campaign for the London Golf Show with a golf simulator," Edwards says. "The average dwell-time is 20 minutes or so and this is the sort of thing people get involved in to kill time."
The biggest leaps forward in customer interaction have come from the development of mobile technology. It is now commonplace for posters and digital screens to have embedded Bluetooth or Hypertag (infrared) technology, allowing customers to download additional information.
This technique was pioneered last year when EMI launched the Coldplay album X&Y and made Bluetooth downloads available through Titan's (formerly Maiden's) Transvision screens. It's also been used on the Tube - Channel 4 made four-minute documentaries available from six-sheets on the network via Hypertag, while TfL distributed the contact details of licensed taxi companies through Hypertag as part of a safety campaign.
Universal McCann's Middlemas says this was brilliant for campaigns like the Coldplay launch but it is not yet as cost effective as it will be once more consumers are familiar with the Bluetooth functionality of their phones. "The cost per thousand will come down as the universe (of consumers using Bluetooth) widens," Middlemas says. "It's still very new at the moment but over time it will become the norm."
Kinetic's Lee has used the Transvision Bluetooth capability in a campaign for British Airways and says, while it wouldn't suit every client, she finds it remarkable how cost effective these type of solutions already are.
There are few advertising opportunities that target commuters and only commuters, although the Metro newspapers are arguably a rare exception. Both radio and outdoor have large commuter audiences, but also reach a wide audience of shoppers, school children, housewives, restaurant-goers and drinkers.
In the outdoor sector, this is changing as new technology allows day-part and week-part campaigns to enable advertisers to reach a more targeted audience.
Transvision is already sold this way - Titan's Edwards explains that the company offers commuter packages where ads are played from 6am-9am and again from 5pm-8pm.
The digital escalator panels on trial at Tottenham Court Road Tube station - which also tick the box for visual impact - theoretically have this capability although they are not yet sold this way.
Viacom's Cheshire explains that day-part and week-part selling will become a reality once the digital escalator panels are expanded beyond one station. However, the screens do offer remote copy updating so, while advertisers must buy a standard two-week campaign, they can change their message for different times of day or days of the week.
"The Independent used it (back in March) to broadcast that day's front page, which made it much more engaging for consumers and more relevant," says Cheshire.
Universal McCann's Middlemas is a big fan of the digital escalator panels - largely because of their visual appeal - and keen to see them expanded across the network.
There is also the challenge of better targeting to reach particular types of commuters. For example, Viacom is currently exploring the possibility of advertisers sponsoring WiFi or quiet carriages on its trains, while Titan offers packs targeting stations in London and the South-East with a high proportion of "affluent" or "urbanite" commuters.
Traditionally, most commuters have found that the mode of journey has dictated their choice of media. Commuters making the journey by car tend to listen to their radio, while bus and rail passengers buy their favourite morning or evening newspaper or pick up one of the many free alternatives.
Now new technology is expanding the platform for both broadcasters and publishers to reach commuters in new ways. Many radio stations and newspapers have jumped into the podcasting world with enthusiasm - for example, Virgin Radio has made flagship programmes, such as the Christian O'Connell Breakfast Show, available as free downloads.
James Cridland, director of digital media at Virgin Radio, says podcasting has allowed passengers on the London Underground to tune into radio content for the first time.
"Clearly listening to radio on the Tube would be impossible," Cridland says. "But with podcasting, unlike standard radio, you can pause and stop and start when you get to your station so it's giving control back to the user.
"You're reaching an audience that has money to spend on shiny Apple products and a computer and broadband at at least one end of that journey. So they've got a certain amount of disposable income."
Cridland says the podcasting audience is still small - there are 110,000 Virgin podcasts downloaded every month compared with 4.2 million listeners tuning in with actual radios - but one that is proving attractive to advertisers.
Mobile services are growing in popularity as well, with everything from news updates via mobile internet to customised episodes of soap operas such as Coronation Street.
Damian Blackden, director of strategic marketing technologies at Universal McCann, says the proposal to allow mobile phone usage on the Underground is potentially appealing because it would allow a large commuting audience access to mobile internet services.
He believes mobile media shows greater promise than podcasting, which is "essentially just time shifting".
"It will be possible to get really rich content - audio and video and mobile TV in whatever shape or form it takes - and it will have a really interesting effect on all sorts of other things," Blackden says. "For instance, it will make search even more important if people are searching on mobile."