Two small boards with two wheels under each board. . . Slide on two boards with two feet respectively. What's this called? Roller skating? Skateboarding?

This is called drift board, not skateboarding or roller skating, but a board after skateboarding and roller skating. It looks like roller skating. Two feet step on a board. There are two wheels under each board, but the feet and the board are not connected, just like skateboarding. This is also very easy to learn and relatively cheap. There are also many people playing now. Here is the picture above.