MaNGOS is rather fragmented, with several different communities all working independently on separate projects. From what I understand:
MaNGOS is the core server.
ScriptDev2 is a separate project which significantly enhances MaNGOS' AI.
ACID is... something which augments ScriptDev2, but I can't find any information on what it does or how it does it.
Of course, the databases are also separate projects seemingly not associated with the above.
Is there really as much separation between these communities as they appear to be, or am I simply not understanding this?