While exploring Bangkok, i was a bit surprised to find so many bikers wearing similar kinda clothing and waiting. On enquiring with a local, i came to know that these are the motorbike taxis, a good way to get around Bangkok during rush hours or if you are the kind of explorer who likes the wind in your hair while you are commuting. They are comparitively cheaper than the regular taxis there and are known to really cut down your commute time.
Take Care,
Ciao