Typically once everyone starts to post we'd follow a semi posting order according to how you relate to each other. If you are in a group talking to one another you'd give others time to respond to each other before posting again. In this case you can post anytime you like. :)  Once we all get going we'll have a basic posting order, loosely based of course. Mostly because some people are on different schedules and such. Just keep in mind civility and posting etiquette with relation to how people might respond to what you say or do.