In the future, cell phone users will be able to leave messages anywhere in the form of what might be termed electronic post-its. They will be able to post virtual messages referring to a specific location wherever they are needed.

Say, for example, that you’ve arranged to meet a friend for a stroll round town. While on your way you can simply leave a digital graffito, for instance at the arranged meeting point: “Just looking at a few CDs in the store opposite, come and join me.” If you wanted to send your friends the same message by SMS you would have to send every single one a separate message. This would be far more time-consuming. Advertising messages could be placed in front of stores to draw attention to special offers. Anyone in the mood for shopping could switch on the advertising mode and wander from one offer to the next. People in a hurry simply switch this mode off. The Siemens developers have shown that the system functions with a prototype produced in cooperation with the University of Linz and the Ars Electronica Futurelab.
A focal point of the research work was to develop different ways of displaying digital graffiti. For the specialists it was a matter of particular importance to use standard commercial devices to enable the new message system to be implemented quickly. As it turned out, a mobile phone with camera function and a very few add-on devices are sufficient to make the messages visible not just in written form but also in a photo of the vicinity. The really clever trick is that the virtual messages are superimposed on the real world (Augmented Reality (AR)). The user can take a picture of the surroundings with a mobile phone camera. The digital graffito is then superimposed on the camera photo. One possible use for this function would be for applications in tourism. Digital messages could be attached to pictures of a local sight to provide information about the building. The radius in which the message can be received can be selected by the writer of the message. Buildings visible from far off – the Acropolis in Athen, for instance – can be given a larger radius of a few miles enabling tourists to read the graffito as well from a long way away.