If you subscribe to the stereotype that techies and developers are an unsociable lot, then this is probably one of the most difficult and arduous things you can think of.
The meet and greet is a customary and necessary step in establishing first contact and introductions to people you've not met before. Like the equally loved and hated "ice-breaker" at the beginning of meetings, it can be a somewhat staged and rehearsed affair. However, it doesn't need to like that. The idea and purpose of a meet and greet are to bring a bunch of people together to develop opportunities for working together, whether you are colleagues or potential customers and suppliers. But if you boil it all down, it's nothing more than a simple get-together of people with a particular shared context.
But what's the goal and role of a manager at a meet and greet...