This means that whoever starts the thread controls where it goes geographically. They should also be responsible for introducing the major events. If the person who started the thread should happen to pull their character out, the thread will be left to those characters remaining.

This means that you are in control of your own character only. Remember, it's not fanfic. This may seem a bit difficult. It also means that some posts will probably be very short, as you will need to let someone you're interacting with supply their own responses.

If you are writing about an encounter with a character from Hercules or Xena, you may control them, since we have no one on these forums assuming their identities.
If someone participating needs to leave for an extended period of time, but does not wish to pull their character out of the story, they may find ONE person to control their character for them.