With increasing incomes in Vietnam, particularly in the big cities and what with it being quite problematic buying a bike over 175cc* a lot of people are buying imported scooters.
Here's a random hot girl with a scooter!!
* above (there is also a different class of license for >175cc which is harder to get - although I know several Vietnamese who have been riding for a decade or more and still haven't bothered to get a license)