Why WordPress creates user name with DASH?

dash username wordpress

Please check ID name in the botoom. Any idea why wordpress is creating dash username?

http://www.seoultouchup.com/forum/

Ex)

Camille Chen, –hong shan yng–, Jane Smith, jacline koh, –Giliane Avice–, eivy joy, –ryan tan–, –Daisy Aw–, –Enso Li–, elaine yip – See more at: http://www.seoultouchup.com/forum/#sthash.arZ0suQp.dpuf