When employees log in to their computers, we ask them to look at a picture of a random employee and then ask them how well they know that person -- the options include "say hi in the halls," "hang out outside of work," and "we're going to be longtime friends." We're starting to keep track of the number and strength of cross-departmental relationships -- and we're planning a class on the topic.
It's one thing when people do that voluntarily on various "social" websites, but being asked to do that at work is a whole different story.
If they're not, in that case, yes, it is very creepy. But I really doubt it.
To provide a software analogy you want the platform group to be friends with the application group and enjoy working together. I've experienced a split myself where one team would just blame the other team for the problems in the final solution and it isn't productive.
Certainly it's not more creepy than FB
FTA, there are about 1,800 employees. It's not clear how they are geographically divided.
2 - The most basic. Think romantic relationships, best friends, business partners, etc.
6 - The "group." Common chimpanzees patrol in groups of six. Next time you go to a party, notice the maximum number of people that can engage in a conversation. Its nearly always six.
Fun tip based on this: If you want to join a lively conversation, walk up to a group of six people and begin to talk to two of them. The group will naturally fission into two groups of three and four.
30 - The "tribe." This is your extended group of friends, or the maximum number of children that can be put in a classroom. Everyone knows everyone well. This group can be mustered to complete a common task without much trouble.
150 - The "nation." This is Dunbar's magic number, derived from the size of the human neocortex. This is the maximum size a group can reach where everyone has at least a passing relationship with everyone else. It is the last natural group size.
Any group beyond this stretches human social instincts, and requires social constructs such as rules or laws to augment it.
Great cultures begin with hiring right. That's not to say you are not awesome, it's just to say you may not be a fit for their culture and their values.