Traits: Presence + Composure
Initiative is a useful tool whenever you need to know who goes first -- or last -- in a situation when order matters. Social encounters are no different, but the normal initiative modifier of Dexterity + Composure doesn't make sense. Initiative in social situations is less about how quick you move and more about how people react to your bearing. Potential situational modifiers include dots in the appropriate Status merit, or a flat +1 from the character's reputation in a field of study, as others yield the floor to her expertise.
As with normal initiative, roll a single D10 and add the result to your character's Social Initiative trait.
Like normal initiative, there is a merit to act faster in social situations: Fast Talker