There's no social metadata anymore. The identify method should return all fields the source knows about. You can default disable fields by overriding the __init__ method in your plugin like this
Code:
def __init__(self, *args, **kwargs):
SourcePlugin.__init__(self, *args, **kwargs)
self.prefs.defaults['ignore_fields'] =[list of fields from touched_fields]
Though I would suggest using threading to make the detailed queries, see the Amazon plugin for an example.