Pencil has developed PASSERBY® technology, electronic word-of-mouth.

Put simply PASSERBY uses passers-by as carriers for electronic information. By using the “social infrastructure” of everyday human activity, it can eliminate the need for more traditional infrastructure like cellphone towers, wifi hotspots and internet cabling.

Each user carries a small portable device, which might be Pencil's SECONDVOICE®, or a mobile phone running Pencil's SECONDVOICE software. Each device communicates wirelessly over short-range, using Bluetooth® wireless technology. As users come in range of each other as they go about their everyday business, the PASSERBY devices recognise each other. They share information about the social network in which their user operates and determine which pieces of information should be transferred between the devices to have the best chance of reaching its destination. The user may later in the day come into range of another user, and so, through the course of a number of interactions separated by human activity, the information is able to find its way through a social network to its destination.

PASSERBY technology can be used to exchange any type of file – audio, images, documents, etc, though it can't provide “live voice” or streaming services. The destination for files can be determined very flexibly, not just by naming users, but also by describing characteristics, so PASSERBY can even provide bulletin-board style distribution to unknown users.

PASSERBY is very power-efficient, enabling the use of solar-charged devices, and can be implemented on very low-cost devices (such as Pencil's SECONDVOICE). Without chargers, cellphone towers and the like, PASSERBY provides a community with rich information access (including school lessons, health alerts, business information and personal communication) completely for free, all for the cost of a simple piece of software or very low-cost device.

You can view or download a one-page introductory PDF here.