Everybody that's ever been to London will probably have been to Picaddilly Circus. And if they have, they will definitely have seen Coke's advertising billboard. It's huge - you simply can't miss it. More so if you work in Marketing -- I even know people who visited Picaddilly Circus just for the signs..

The news today is that Coca-Cola is now also using bluetooth marketing in Picadilly Circus, around it's billboard, in order to make multimedia content available via bluetooth to commuters, tourists and passers-by, promoting its 'Happiness Factory' ad:

The iconic cola brand enjoyed a 3.6% boost in retail sales in 2008 and its best January sales this year, despite the increasingly gloomy economic news. Annual retail sales for Coca-Cola in the UK reached £514.5m by the end of 2008 - nearly a third of the overall cola sector, according to AC Nielsen data.

The new ad, shown on MediaGuardian.co.uk, created by Wieden + Kennedy Amsterdam, is the latest instalment in the Happiness Factory series, which started in 2006. The ads show animated characters who make Coca-Cola in a magical land inside the vending machine and in the latest version, both the human purchaser and the Happiness Factory workers are tired and in need of the uplifting effect of a Coke.

The campaign is global but will launch in the UK on Tuesday. The multimillion-pound UK campaign, bought and planned by Vizeum, includes TV, radio, online, outdoor, mobile and a cross-promotion with Xbox.

The Xbox partnership includes a giveaway of 3m Xbox loyalty scheme points, online gaming gurus giving tips and advice and a Coca-Cola skin to let gamers customise their Xbox dashboard.

Online elements include a "Happiness Hub" microsite on Bebo and an MSN games application and music track. Consumers can also download Happiness Factory ringtones for free from the Coke's Piccadilly Circus billboard using bluetooth.

Coca-Cola needs no introduction, and it's often involved in bluetooth marketing campaigns (and is doing a pretty good job of filling my articles, too! :) ). Here's a couple of relevant past articles:

• Bluetooth Marketing Network in China

• Coca-cola via Bluetooth

Though, I've not personally witnessed the campaign, and don't know all the details, it's important to note that they have chosen to allow the public to download content, rather than just spamming everyone passing by. By making the mobile marketing campaign interactive, and thus opt-in -- rather than opt-out -- they have distanced themselves from any SPAM accusations, only providing the service to everyone choosing to participate.

It's all about putting the control in the hands of the consumer, and giving them the option to participate. If they do, they're a lot more likely to lead to conversions.