I've been watching the discussion trying to figure out the DIY City's wavelength.
I think part of what we see emerging on the local (neighborhood) Issues Forums hosted by E-Democracy.Org fit your model of citizen problem-solving. My experience is that at the very very very local level people will pick shovels and do stuff, while up the chain people prefer their tax dollars to do the work so they don't have to be bothered.
On my local neighborhood Issues Forum - http://e-democracy.org/se - we've had people start community garden efforts, ask if people want to do a blood drive and then promote it, suggest and then organize a volunteer lake clean-up (only to run into trouble getting connected to the right person in the parks department for permission), buy flower bulbs in bulk for their homes with some left over for public space, etc. Recently, a mugging at a new local light rail stop generated a flurry of activity: http://blog.e-democracy.org/posts/355
Anyway, since a number of you will be at Participation Camp, I thought I should say hello. If any of you would like to talk neighborhoods online to gather tips from 15 years on the front lines of e-participation, check out the two sessions I'll be leading or virtually note - http://e-democracy.org/if - for an existing Webinar and some links here: http://pages.e-democracy.org/Social_media_in_local_public_life
I'd like to know if there is some web downloadable open source software or free service allowing to manage a barter system.
Here in my city we have a place where periodically people meet to exchange stuff.
A web service where everyone can show the stuff who's going to bring on the programmed meeting, and users can say they're interested in something or another, specifying what they'll offer in exchange for that, and eventually receiving answers like "that will be ok", or "no way man".
Not a system to "place" a real order, just a system to show the stuff you want to give out, and attract potential users interested in it. The "real thing" is always the periodic live meeting.
I wonder if something ready could be used for this, supporting photos, tags, votes, etc.
Our project, http://suddenly.org , uses print publications, visual art, public gatherings, and conversation to pursue the same political forms and futures that DIYcity catalyzes with newer technologies. We publish books, present visual art, invite people to gather, eat, and talk together, and then we write about it and bring the conversation to new places and people. This activity has taken shape across a huge geography. From Sergio Pastor's suddenly post 10/3/08 http://suddenly.org/?p=593 : "Suddenly is not only an inquiry, but also an attempt to enact a new urban form of gathering and dispersal — a deliberate form aimed at the creation of a public, a publication. This new urban form [is] a directed attempt to take inspiration from the models and possibilities of the organization of resources provided by new urban patterns in order to take these new patterns seriously." From DIYCITY: "How can these technologies — Twitter bots, aggregators, social software, mobile apps — be applied to transform urban spaces, changing them from the centralized, hard-coded things they are today into finely-tuned, fluid, user-operated systems that are efficient, sustainable and fit for life in the 21st century?" Suddenly asks the same question, but of the older technologies of printed matter and physical gathering and conversation. I think the awesome common path ahead for us is to bring these older and newer technologies together in a a big robust ecology of self-inventing, shifting, morphing cities.