I feel that anything that has competition, it's a sport.. And skateboarding is a sport.. But it's kinda risky and takes a lot of practise though..
its a sport because its something that people practise and work hard for.. and its also physically challenging... got a couple of friends who got injured while playing skateboard and entered competitions...
it depends. I skate, a lot. But I don't skate for competition, which is what i define sports as. so for me, its not, but for some, it is.