I suppose it was inevitable: coathangr, which describes itself as "social networking for your pants." Less whimsically, it also says it's a "social network for sharing fashion advice," and finding people who share your fashion taste.
It would be interesting to see how the system is used. Does it actually encourages better fashion sense? Is it used maliciously by people giving intentionally bad fashion advice?
On a more serious note, this is a good example of what Jyri Engstrom calls "object-centered sociality:"
the term 'social networking' makes little sense if we leave out the objects that mediate the ties between people. Think about the object as the reason why people affiliate with each specific other and not just anyone. For instance, if the object is a job, it will connect me to one set of people whereas a date will link me to a radically different group. This is common sense but unfortunately it's not included in the image of the network diagram that most people imagine when they hear the term 'social network.' The fallacy is to think that social networks are just made up of people. They're not; social networks consist of people who are connected by a shared object. That's why many sociologists, especially activity theorists, actor-network theorists and post-ANT people prefer to talk about 'socio-material networks', or just 'activities' or 'practices' (as I do) instead of social networks.