Brooklyn, not sure why this would be a MO vs Charedi thing, since neither school of thought was around back then.
What I learnt about it, was that each marragiable young woman borrowed a white dress from someone poorer than her, and went dancing in a field, where a man would pick her out. Then they would get married.
Truth be told, it does sound a little strange, so there may be more to it than that, or my memory is completely wrong, so maybe someone who is more knowledgable can answer 🙂