I recently started to play quidditch, muggle quidditch that is. I'm a keeper, like in every other sport I play. When I talk about being a (not very good) soccer keeper or hockey goalie it's respected as a sport. When I mention quidditch, the reaction is a mix of people thinking it's really cool and people laughing it off as not a real sport. The positions are pretty much the same as any other sport, a chaser is a forward, a beater is a d-man, a seeker is a specialized forward and a keeper is a keeper/goalie. Even though I've only done a 2 on 1 scrimmage so far (a beater and I playing against a chaser), I know it's about as hard to keep a quaffle out of a hoop as it is to keep a soccer ball out of a net or a puck out of a net.
I understand that being a fairly new sport and one based on a fictional book, some people will laugh off quidditch, but it is a real sport. Hockey has the Stanley Cup and other competitions such as the Olympic and Worlds, soccer has the World Cup, the Olympics and numerous other competitions. Quidditch has the World Cup and is gaining in popularity.
When Isobel Stanley first put on a pair of skates and picked up a stick, hockey was a new sport. When the first group of school boys started kicking a ball around, soccer was a new sport. Now they are popular worldwide. Hopefully quidditch will get there. I know I'll get people laughing it off, but to me quidditch is a fun sport and isn't just the sport on broomsticks as written by JK Rowling.