Studying the social relationships between people is an area that is getting an increasing amount of attention.  Sociologists often turn to concepts from the field of network analysis to help them understand and quantify these ideas, such as how central a particular person is within their social network, or which subgroups of people are closely related (see Social network). 

These techniques involve applying complex algorithms to large sets of data.  What we need is a platform that can store the data, give us a framework to implement the required logic, and a flexible way of presenting the data to users.  SQL 2005 has all the necessary components, so I've attached a paper that describes how to start tackling this area.  The paper walks you through creating the data mining model using the Microsoft Association Rules algorithm, developing the stored procedures using C#, and then reporting on the data mining model.