Joining multiple disparate data-sources, commonly dubbed Master-Data-Management (MDM), is usually not a fun exercise. I would like to show you how using a graph database (Neo4j) and an interesting dataset (developer-oriented collaboration sites) to put the fun back into MDM. This approach will allow you to quickly and sensibly merge data from different sources into a consistent picture and query across the data efficiently to answer your most pressing questions.
You can read the associated blog posts on my blog. The blog posts cover the hows and whys of the project, while this and other GraphGists will examine how to answer specific questions of the data.