Urballoon (urban balloon) by Carlos J. Gomez de Llarena is:

a balloon equipped with a projector and wireless connection to the web that enables people to submit content online and broadcast it in public spaces.

Tethered in pedestrian areas the balloon becomes a means of displaying dynamic information on a technological par with advertisements yet avoids the infrastructure that controls these and it’s accompanying costs / censorship / fixed location.

Our conventional understanding of the urban condition and the distinction between private and public space has been blurred by the evolution of technology…Urballoon is a probe being introduced into the flows of our current urbanity. This experimental architecture seeks to juxtapose emerging notions of mobility, P2P networking, syndication and blogging with traditional uses of social space, broadcasting and outdoor advertising.

A political underpinning of the project is established by the commitment to excercise free uncensored speech, empowering citizens to seize it as an urban broadcasting channel.

Related work includes The Media Cartridge.