I assume that you are talking about citation styles. See the documentation on how to add more of these

http://www.zotero.org/support/styles

pretty sure romanov is refering to disciplines in the profile:
https://www.zotero.org/settings/profile

For people who want to use Zotero as a more broadly academic social networking tool those would seem to be important.

edit: seriously? It took me less than 3mins and he still beats me.

well, that's a bit harsh - every possible list of disciplines will always be incomplete -
currently the list has area studies and religious studies - near-east (or middle-east or whatever one calls it) and Islamic Studies fall under those higher level categories (so technically it's not incomplete in this respect, just a bit coarse).

I don't have a strong opinion on what criteria to use to add disciplines, but at some point there needs to be a cut - should that be regional (i.e. we include European, Near East, East-Asian, Latin American etc. studies). But then, what about individual countries and sub-regions? China studies? Western European Studies? Central America Studies? etc.

I would imagine that the "about" fields would facilitate scholars finding people with similar interests and describing what they do in appropriate terms.

@adamsmith: I realize that making a list of disciplines is tricky in many ways: academia.edu has what seems to be an open list - although it is a list of interests, not disciplines - and it is messy.

Yet it would be nice if a discipline one is getting a PhD in is available for choosing. In any case, the available list is way too coarse: even together, the disciplines that I selected tell absolutely nothing about me as a scholar. Yet, I do not really have an answer on how it should be organized. Perhaps, "interests" is an answer (well, if ZoteroPeople are willing to add it).

On a second thought, it would be nice to have something like this:

1. Everyone can create his/her own list of interests (limited amount of words for each interest, say X - if X is too many, let it be Y :).
2. This list is visible in everyone's profile and each interest remain private until:
3. more than 50 people share it (50 is an arbitrary number here, of course). At this point it becomes public and visible to the entire Zotero community.
4. Now, everyone can add their custom interests as well as to select those from the list.

I have no idea how to do this technically, but it does not sound like too much of a work. This will allow to keep the list of interest relatively short and very effective for network building in the Zotero environment.

Since "the Initiative is punishable," as the Russians say, I am ready to maintain the list of interests :)