Walking dinner means there's no buffet, but there's a waiting staff walking among the guests with bite-sized meals. You're at the mercy of the staff for your food, and it almost invariably ends with people being hungry.

In Rotterdam, there's a few places which specialize in corporate dinner parties with "walking dinners". It's a fairly popular way of organizing dinners, because for a relatively low cost you get a relatively glamorously-looking dinner for a relatively high amount of people in a relatively small-space (since the guests stand during the dinner).