I've always wondered the logistics of WWE. Is every match choreographed completely, or are 'they' just like "you dominate for the first 5 minutes or so, then a momentum swing, he attempts a finisher, you counter and you pull off the upset." And by 'they', who are they? Is Vince out the back and runs the wrestlers through every match and how it's going to go down, or are there others, or what? I've always wondered this.
Most matches aren't completely choreographed. In fact, the only one I can remember is Warrior/Hogan from some Wrestlemania many years ago, mainly because it was supposed to be a huge match and they didn't want anything to go wrong.
For your everyday match, however, the booker/writing team decides who will win and how (Pinfall, run-in DQ, count-out, etc.). The wrestlers will then work out a rough outline of how the match will go. They may discuss it with other wrestlers or road agents (Who are often former wrestlers themselves) to get ideas on how to make the match more exciting or flow better, but by and large, the matches are called in the ring between the wrestlers themselves, and the referee, who may pass information between the two or tell them when to 'go home', or head into the finishing stretch.
The wrestlers are all pretty familiar with each other's spots and signature moves and can usually tell what move is being set up if it's going to be a big move. For example, The Rock always did The People's Elbow after he hit a spinebuster, so if Wrestler B got hit by that, he knew to lie there while The Rock did his thing. But for smaller things, like reversing an Irish whip or hammering on a body part, the wrestlers themselves will usually call that on the fly in the ring (You can watch almost any Botchamania on Youtube to find examples of guys audibly calling moves in their matches).