I know it's a Q&A site, but does it fall under the umbrella of social networking? There's a raging debate here at work, so I thought I'd put this question to the community.
According to Wikipedia:
A social network is a social structure made up of individuals (or organizations) called "nodes," which are tied (connected) by one or more specific types of interdependency, such as friendship, kinship, common interest, financial exchange, dislike, sexual relationships, or relationships of beliefs, knowledge or prestige.
So I'd say no. It would seem like connections between the nodes is the definitive feature of a social network and we don't have that.
Stack Overflow forms a social structure, wherein we have patterns that define our relationship to the site and to each other.
While social networks almost always exist within every social structure, social structures need not formalize or recognize the networks that form within them. Stack Overflow is a good example of a social structure that does not recognize the social networks that are formed within its cultivated social structure.
Social networks come in a variety of forms, and for very broad definitions Stack Overflow comes close. However, one of the defining characteristics common to nearly every social network is that people define specific interpersonal relationships within the social structure.
People are forming such relationships within Stack Overflow, but the site and software do not formalize these relationships.
I wouldn't say that Stack Overflow is a social network until the site and software themselves formally recognize those relationships.
In fact, far from supporting social networks, Stack Overflow has a few features that discourage social networks from forming within its social structure. If you want to talk to a given individual, your only on-site option is a public comment on one of their posts. While you and someone else may share in common your knowledge of Ruby, unless you encounter them off site you may never know that you also share the enjoyment of, say, painting. Chat fills the gap a little bit, but only for those that choose to participate.
The above answers give an academic, textbook-like (and dare I say, inconsequential) analysis to the question. I'd like to offer a practical perspective that business strategy planners (such as Facebook's CEO) should care a lot more about.
Anecdotally, I get my fill of bonding with other human beings via Stack Overflow to the point I am not as compelled to use Facebook to partake in this attention economy trade. Seeing one of those red balls in the Stack Overflow menu bar gives me the same acknowledgement of my existence by other beings, which the human evoloutionarily (?) craves, as those red alert sprites that Facebook's menu bar does.
This is significant from a competitor analysis point of view. Stack Overflow is a substitute product for Facebook within a certain demographic. So I would say yes it is a form of social networking.