Thanks for the mention (I'm Chris from http://www.gusta.com and previously Airbnb). I do think a distinction should be drawn between "an Airbnb for food" (where regular people are cooking for strangers) and the established "pop-up" movement, often hosted by professional chefs. The first is a social site with a payment layer and the second is a ticketing site with a social layer.

Longer term, I think both models can coexist as they are approaching the industry from opposite ends. "Legality" is going to be an issue for any disruption in the food market - dealing with that is the cost of doing business. Personally, I hope Gusta gets to a point where people care enough to want to regulate us :)