It's also interesting that there's no sense of time here -- my Berkeley I-school connections are 2-3 years old, but those connections appear much more substantial (and central) than my (current) Stanford Communication connections or my brand-new Values in Design connections. Similarly, my UCBD links appear more extensive and central than my connections to other dance communities, though those connections are generally at least three years old. And I haven't seen most of my high-school "friends" since high school, and I wasn't even close with many of them then. There's also no sense of the type of connection -- professional contacts vs. social contacts (e.g. dancers) vs. close friends, for instance.
This also attests to the small-world nature of the Bay Area, which I generally rediscover at any reasonably heterogeneous Bay Area party. While the links aren't as dense as the within-group links, there's still substantial overlap between these various groups, particularly the dancers (upper leftish), bab5 (appropriately central), and the sociotechnical researchers (lower left). It is also interesting to me that there's actually some overlap between my high school friends and other contacts, largely because of visits I've made there or visits friends have made to me.