My facebook cluster
836 friends / 4 years FB usage
My clusters seems to be either event-based, or interest-based but I realize that you wouldn't really add somebody on facebook unless you had the opportunity to meet the person in person or in some form of online community. So within a cluster, the people may be spread out worldwide but at some point in time, we were together at one place.
But I noticed I also have a lot of people spread out with no cluster. That's because we have no other mutual friends or other mutual events. Seems like each cluster is a mini network of its own that spans different geography connecting people with shared events in their lives. Facebook is limited by your ability to have come in contact with that person at one point in your life or other. This could even be people you meet over facebook apps. How then do you explain geography of facebook apps?
And some clusters have too many overlay of representations. Like my group of primary school friends is lost under the labels of other clusters.
Nowadays, the first thing after 30 minutes of meeting somebody, i will usually ask, "do you have facebook" and skip the contact details by saying "no worries I'll just add you on facebook".
I find it interesting that my family network runs in parallel clusters. one for each side of the family!
Does geography matter for example like my cowboybar barflies cluster - I've never met half of those people and they can be in another world for all that matters. What is geography? Virtual space is a form of space after all.