Social networking looks like an interesting way for people who share interests to communicate with each other. The ALIA Symposium "beyond the hype" site was an interesting example of this. People from the library world who attended the symposium continued to discuss the issues raised through the Ning site they set up.
Such networking has other potential benefits. Specialist librarians for example, could connect with individuals in the community with an interest in their speciality. The profile of the library and thus the use of its resources to contribute to the collective knowledge is one way of broadening the library's reference services.
It was also interesting to see how different people in some of these networking sites identified themselves. Some were quite open providing an image of themselves, their full names and the area they lived. Others were more circumspect. Personnally I value my privacy so if I were become part of such a network I would be inclined to use a psuedonymn and an illustration rather than a photograph of myself.