We offered up an initial answer to this question on our blog - placekraft. We'd like to take the opportunity to post here at Platial to refine the definition and open up the discussion to a broader audience.
Neogeography, in its most basic sense means - new geography. We would offer that the prefix "neo" implies more than just new in its usage. Neo also has a connotative meaning, something akin to "in the manner of." Well, "in the manner of what?" is the question.
Neogeography, as we see it, is a diverse set of practices that operate outside, or alongside, or in the manner of, the practices of professional geographers. Rather than making claims on scientific standards, methodologies of neogeography tend toward the intuitive, expressive, personal, absurd, and/or artistic, but may just be idiosyncratic applications of "real" geographic techniques. This is not to say that these practices are of no use to the cartographic/geographic sciences, but that they just usually don't conform to the protocols of professional practice. For an example of the personal application of mapping one need only look at the impetus behind founding Platial in the first place:
"We ended up with a kitchen drawer stuffed full of these notes. It was our collection of Places, plus menus for take out, magazine articles listing kid friendly museums, schedules of parades, and a few brochures and tour books for attractions that seemed interesting enough. A few maps got lost, loaned out or recombined, others got photocopied or emailed or taped to front doors as invitations...We wanted a way to preserve all that knowledge in a powerful, useful, contextual way.
We started asking my friend Jake about the technology side of building something to address this, and discovered he'd been working on, and thinking through some of the same issues. Our talks got more and more exciting as we saw the potential for a broad, useful way for people to share contexts and meanings of Places.
So here we are, launching a service that we hope can do some of these things (and maybe a whole lot more) for people."
Most maps on Platial fall well outside the bounds of professional geography, but still provide, thoughtful, engaging, and/or just plain entertaining information. They do in fact offer, as the founders of Platial envisioned, a "useful way for people to share contexts and meanings of Places." And this is something at the heart of what neogeographic activities are to us.
Platial, however, is just one example of a broad field of activity that includes urban exploration, site specific sculpture, land/earth art, geo-tagging, guided walks, ephemeral cities, imaginary urbanism, altered maps/radical cartography, travel writing, psychogeography, place based photo blogging, etc. What connects all of these activities? There may not be a clear answer, but we would say they all comprise, or fall under the rubric of, neogeography.
Hopefully, this provisional definition will allow us to start a discussion, to share, in the spirit of Platial, our collective ideas and resources to build something interesting and meaningful.