According to Wikipedia, desire lines (or social trails) are the trails which manifest on the surface if people heading for a certain destination take a shortcut through the grass. This great post further explains the concept of desire lines, and discusses why landscape architects should take this human behavior into account before planning pathways. The map of the Michigan State University shows an example were architects waited until desire lines emerged and paved them afterwards.

Sometimes we GIScientists struggle with the phenomenon of the rise of geospatial applications in the web (i.e. Google Maps, OpenStreetMaps, Flickr, ...). In the past we were told that research is targeting the theoretical foundations of GIScience, and that the stuff we develop is years ahead of the products available on the market. But the web, Virtual Globes, or the abundance of GPS devices changed everything. This all developed so fast that we have a hard time to catch up. In fact, all we can do is to react and try to understand what's going on.

I like the analogy of desire lines and the ongoing social phenomena of the web. In the past we were the architects who decided how people interact with the concept of space, today we need to study the human behaviour in the web and study the emerging desire lines. And once we know what the people care about we can try to pave the ways and provide the theoretical foundations for the geospatial web.

In the book Swarm Intelligence from James Kennedy and Russel C. Eberhart, the authors introduce examples from nature, namely fish schools and bird flocks, as examples for social organisms. The actions of individuals are usually very simple, but the whole group seems to act intelligent. A school of fish "appears to move as one, with hundreds if hundreds of thousands of fish changing direction, darting at what appears to be the same exac instant". To avoid being easy prey, animals group together (a nice model of these phenomena is presented in Hamiltons paper "Geometry for the selfish herd").  They claim that each individual acts selfish: each fish tries to avoid to outermost zone of the swarm.

In his recent talk at Annual Meeting of the Socienty for Expermental Biology, Stefano Marras presented the work of him and his collegues about the behaviour of mullets. They simulated aerial predator attacks on a school and used high speed cameras to record the reaction of the individuals. The interesting thing here is, that the escape strategies of each individual of the school followed a chronological order. There seems to be a ranking between the fishes, giving certain individuals (perhaps the leader of the flock?) the right to escape before others.

It seems social networks act the same way. Flat communities like Wikipedia don't have imposed formal hierarchies. But there's always a small group of users which is more important to the whole community and every other user wants to belong to this small group. There's always a ranked order, maybe unknowingly. The work of Marras et al. showed that social organisms in nature, like schools, flocks, and herds have hierarchies (perhaps even swarms like ants and bees?). Why should it be different in web communities? Why do we think that every individual is equal (take the swarms algoritms as example)? We need to be aware of the fact that hierarchies always emerge within a group of people and should think of ways to formalise and exploit them.