From the commissioner:

After the existence of changelings was revealed, Twilight Sparkle made it her business to learn more about them. One of the first things that she found out was not only that there is more than one changeling hive in Equestria, but also that they exhibit a lot of variety. Each hive population has a distinctive coloration and build, and also a dominant field in which they interact with the pony population. This collage shows representatives from each of the six hives that make their home in Equestria.

The hives, with the exception of that of Chrysalis, are currently acknowledged as independent states within the borders of Equestria. While the hive queens are absolute rulers within the hive, changelings are subject to the same laws as ponies outside of the hive, and must comply with Equestrian authorities. The land directly above the hives are regarded as treaty zones where dual authority is shared. The locations of most of the hives is still a secret to all but the highest authorities in Equestria. Few beside the princesses have visited them, although some are allowing pony scholars in to study their societies. Not all changelings leave the hive. In fact, only a portion of their population ever interact with ponies outside of the hive as emotion harvesters, while the rest are concerned with responsibilities within the hive.

While each hive has its specialties, it must be emphasized that they are not limited to those. In fact it's necessary for all hives to have skills in most areas simply to maintain their hives, and to fill the needs of the communities in which they place themselves. Also, while each has a preference in taste of emotions, all of them can get the most nourishment from love. A changeling who has a job that fulfills their primary trait and is in a relationship with a pony has the best of both worlds.

I have been building on the changeling fanon in my stories ( http://www.fimfiction.net/user/Goldfur ), and I will follow up each of these changelings types with a solo description. The hive's dominant traits will be given, but it must be noted that there is a lot of overlap between the hives, and even the most dominant trait does not necessarily hold true for all of its members. Other hives exist outside of Equestria's borders, but only the Western Hive near Griffonia has been revealed at this stage.